单选题 What is said about the development of the helicopter?

A、 Helicopters have only been worked on by man since 1940.
B、 Chinese children were the first to achieve flight in helicopters.
C、 Helicopters were considered more dangerous than the early airplanes.
D、 Some people thought they would become widely used by average individuals.

【正确答案】 D

【答案解析】文章第三段指出，人们梦想乘坐直升机上下班，期望它能够像如今的班机一样运载大量乘客。故答案为D。