An analyst does research about various companies and stocks. A company has experienced stable earnings over the previous years and the company has a high beta. These factors best describe a:

A. cyclical company and a defensive stock.
B. defensive company and a cyclical stock.
C. defensive company and a defensive stock.

吗啡对中枢神经系统作用中，"作用脑干极后区，可被纳洛酮对抗"属于（）

A.催吐

B.镇咳

C.缩瞳

D.抑制呼吸

E.镇静和欣快感