【正确答案】 A

【答案解析】[听力原文]
   In my line of work, I receive a lot of e-mails. I also send a lot of e-mails. Though social media and messaging apps have taken over some of the roles from e-mail as a form of communication, e-mail is likely to retain an important role for business communication in the future. Surprisingly, though, a lot of companies and organizations lack formal guidelines for e-mailing. As most of you will soon be entering the workforce, I would like to share with you my own rules for e-mailing.
   If someone sends you an e-mail, reply to them, acknowledging the email. A simple "thank you" lets the sender know that their email has arrived safely, that it has not been lost among what could be 50 other e-mails that have arrived in your e-mail inbox that day. It is not necessary to reply to a mass email sent to numerous recipients. These e-mails are often informative rather than personalized correspondence requiring a response or action. But it's common politeness to respond to a personal message, preferably within 24 hours of receiving it.
   It's also important to use proper English. Just because e-mails are a quick form of communication doesn't mean e-mails, especially business e-mails, should be written using informal, shortened forms of words. Think of e-mail as a letter. Spelling, grammar and punctuation should not be overlooked. And never use capitals to emphasize a word or words in an e-mail. It's the same as yelling.
   What does the passage say about e-mail?
本题问关于电子邮件，这篇短文说了什么。录音提到，虽然社交媒体和通信类应用已经取代了电邮的部分功能，但电邮在未来的商务交流中仍很重要(retain an important role for business communication in the future)。A与此信息对应，选项中的remain与录音中的retain“保留，保有”同义，故选A。
   录音并没有提到电邮和通信类应用的关系，B“很可能成为各类通信类应用的竞争对手”没有根据。C“逐渐被社交媒体取代”与录音内容相反。D“必须被特定的规定约束”语气过重，虽然说话人提供了一些发电邮的建议，但这仅仅是“指引(guidelines)”而已，并非具体的specific rules。