【正确答案】 B

【答案解析】[听力原文]

Technology: Mobile Phone

Professor: Okay, everyone, let"s take a seat and get started. Today I would like to discuss the use of mobile phones. I"m sure most of you stay in touch with your friends using your cell phones. Mobile phones have come a long way since their introduction and have advanced by leaps and bounds in regard to technology. In Korea, many phones nowadays can even be hooked up to a small mobile TV. Users of cell phones have also increased markedly over the years. In Canada, roughly 69% of people between the ages of 15 and 69 own a mobile phone. The number jumps to 93% in Sweden, where they have the highest mobile phone ownership.
We need to bear in mind that the mobile phone has not been accepted by everyone. Some skeptics believe that the radio waves emitted by the phone can cause serious damage to your health. Scientists back up this belief because they have known for many years that radio waves can cause heating of the skin and affect cells in the nervous system. In fact, people who regularly come in contact with strong radio waves have complained of memory damage and the ability to reason and the loss of control over body movements and heart rate. Due to these complaints, safety guidelines for working with powerful radio waves have been introduced. For people like you and I who don"t come in contact with strong radio waves on a regular basis, the safe limits are less than those recommended for workers. So what do these findings have to do with the mobile phone? Well, mobile phones work on the lowest power possible. As a result, the radio waves they emit are minimal. Although it is not specifically connected with any health issues, people are still concerned.
What"s the bad news? Well, these guidelines are based on negative effects caused by the heating of tissues, such as your ear and head. Don"t worry though, because although mobile phones do warm-up when we use them, this heat is not powerful enough to cause damage to us. Bear in mind that there is still some reason for some concern though.
A group of scientists looked for any health threats from mobile phones. They found that with the current safety laws there is no evidence of negative health effects caused by radio wave radiation. However, they were unwilling to call the mobile phone "safe" due to the need for more research. They also found that radio waves may affect biological cells but this may not necessarily lead to any particular harm to the adult mobile user. This cannot be said for small children though. Because their skulls and cells are still growing, it is easier for radio waves from a mobile phone to enter their heads and their skin tends to absorb more radiation compared to adults. The scientists concluded that children should only use mobiles for short, important calls. The scientists also recommended that the general public would benefit from mobile phone manufacturers publishing the amount of radio wave energy that each handset transmits to the human body. This would better inform the public of any possible risk. Although there is no evidence of a risk to the health of people living near base stations, radio wave emissions should be monitored, especially near schools. Another controversial issue regarding mobile phones is whether drivers should be able to talk on the phone. I think we can all agree that talking on the phone while driving should be discouraged.
In order to satisfy critics who still think that mobile phones emit an excessive level of radio waves, the hands-free phone has gained support. The hands-free phone has many benefits including the decrease in strength of radio wave radiation due to the increase in distance of your head to the handset. Rather than holding your mobile phone against your ear, which increases your exposure to radio waves, you can now place it in your lap and still talk to someone with an ear-piece cable. This new solution still has problems. One study found that when the phone is in an exact position and the cable is a specific length, the ear-piece cable actually directs more radio waves into the user"s ear. To solve this unlikely scenario, some overly concerned users might find a shield that can protect them from radio waves useful.
By and large, studies have shown that mobile phones do not place adults at risk, unless they are driving and talking on the phone at the same time. Moreover, hands-free phones are a good alternative to holding a cell phone next to your ear. Ongoing research should still be conducted to satisfy the unconvinced public who may still have some health concerns.

[解析] 讲座中解答此问题的关键句为：The scientists also recommended that the general public would benefit from mobile phone manufacturers publishing the amount of radio wave energy that handset transmits to the human body.其中需要关注的关键词句为benefit，publishing the amount...可见B与科学家的建议相吻合。