单选题 Which of the following is not TRUE of the investigation?

A、 It will last at least 7 years.
B、 Cooperation from the mothers is also necessary.
C、 Some independent observers play a part.
D、 Researchers paid site visits to see a caretaker's personality and kids' emotional reaction.

【正确答案】 D

【答案解析】[注释] 本题的关键是将每一个选项的内容在短文的最后一段进行对照确认。前三个选项的内容都可以找到依据，而D选项的意思不同于短文最后一个句子的意思，原文中是通过看录像而非去现场进行观察。