All of the following could be objectives of a passive investor in commodities, except:（）

A. Risk diversification.

B. Inflation protection.

C. Anticipating good performance during periods of economic growth.

对怀疑直肠癌的病人，首先应作的检查是（）

A.乙状结肠镜检查

B.直肠指检

C.X线钡剂灌肠

D.大便常规检查

E.纤维结肠镜检查