He had studied hard, he would have been able to pass the exam.()

A. He had studied harder

B. If only he studied more

C. Had he studied harder

D. When he studied more

个体处于应激状态时，表现出心率加快，血压增高，呼吸加速，血糖升高和肌张力增强，这些生理反应说明活动增强的神经内分泌系统是（）

A.下丘脑-垂体-甲状腺轴

B.下丘脑-垂体-肾上腺皮质轴

C.交感-肾上腺髓质轴

D.下丘脑-垂体-性腺轴

E.下丘脑-垂体后叶轴系