一般认为证券市场是有效市场的机构投资者倾向于选择（）证券组合。

A．收入型

D．平衡型

C．市场指数型

D．有效型

The primary reason for withholding food and fluids from a client who will receive general anesthesia is to help prevent

A．constipation during the immediate postoperative period.

B．vomiting and possible aspiration of vomitus during surgery.

C．pressure on the diaphragm with poor lung expansion during surgery.

D．gas pains and distention during the immediate postoperative period.