单选题 The research described in the passage is primarily concerned with answering which of the following questions?

A、 How can researchers control the effects that LSD has on behavior?
B、 How are animals' reactions to LSD different from those human beings?
C、 What triggers the effects that LSD has on human behavior?
D、 What technical advances would permit researchers to predict more accurately the effects of LSD on behavior?

【正确答案】 C

【答案解析】读完全文知道，之所以研究the effects of hallucinogenic drugs on the brain alit on behavior与serotonin的关系，就是为了找出LSD在人体内发生作用的真正原因，故选C。