单选题 Why does the writer say "You might be forgiven for thinking that ... "?

A、 Solving the mystery of sleeping and waking requires new insights.
B、 Most of the other things people do regularly are biologically straightforward.
C、 The problem sounds rather grand.
D、 We still lack for progress though we' ve spent much more time studying it.

【正确答案】 D

【答案解析】[试题分析] 本题为推理题。
[详细解答] 问为什么作者说人们认为睡眠研究人员整天睡大觉是情有可原的。第一段第二、三句说，对于吃喝拉撒等人类活动，研究人员已了如指掌；而对于占据人们日常生活更多时间的睡眠，虽然进行了长期的探索，但至今仍是一个迷。这是对第一句的解释。D项与该信息符合，故为正确答案。