所以C项为正确答案

B  录音中提到“The researchers asked 4,113 people about the Net’s impact on daily activities.”(调查者问了4113个人，关于互联网对日常活动的影响)，由此可知这里只有一个课题，所以题干的表述是正确的。

C

What are the right things? First of all, do your homework; learn every thing you need to know about your business or profession before 40. Second, develop your own style. Before you’re 40, learn what you’re comfortable with, whether it’s in the way you dress or simply the small touches that set you apart. Third, put your emotional life in order, if possible. It’s a great help, when climbing toward the higher rungs of the career ladder, to be happy in life, rather than to find yourself mired in emotional crises. It’s hard enough to succeed without taking on personal problems that sap your energy and divert your attention. Besides, unhappiness is like a disease — it gradually eclipses interest in everything else.

【解析】根据原文“He always finds fault with everything.”，意思是：无论什么事情，他总能挑出毛病。本题的关键是理解词组find fault with的意思，该词组意为“对……挑毛病；挑剔”。选项D中的overcritical“过分挑剔的；吹毛求疵的”与此意思一致，所以C项为正确答案。