单选题 What can we learn from Paragraph 3?

A、 Subjects are supposed to modify the perception of stress and their reaction to it.
B、 Subjects are supposed to relax themselves in stressful conditions.
C、 Subjects are supposed to learn to slow down physical activity.
D、 Subjects are supposed to adopt new hobbies that are separate from their careers.

【正确答案】 A

【答案解析】文章第三段所述让A血型被试者尝试做的事情，旨在让他们调整自己对压力的感觉，并控制自己在压力环境下的反应。[B]文章未提及。[C]和[D]是做这种调整的具体的方法。