Question 24 is based on the passage you have just heard.

    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, (22) 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.

    (23) If someone sends you an e-mail, reply to them, acknowledging the email. A simple “thank you” lets the sender know that their e-mail has arrived safely, that it has not been lost among what could be fifty other emails that have arrived in your e-mail inbox that day. (24) It is not necessary to reply to a mass email sent to numerous recipients. These emails are often informative rather than personalized correspondence requiring a response or action. (23) 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. (25) And never use capitals to emphasize a word or words in an e-mail. It’s the same as yelling.

24. What does the passage say about a mass e-mail?

解析：录音中间部分指出，群发邮件通常是通知性的，而不是需要回复的私人邮件，可知群发邮件是不需要回复的，故C选项为正确答案。