An analyst does research about cost of capital. All else constant, if a company's marginal tax rate increases, the weighted average cost of capital most likely:（）

A. decreases.

B. remains unchanged.

C. increases.

我国人口老龄化的特征没有

A．人口老化速度快
B．老年人文化低
C．经济基础薄弱
D．城市老年人多
E．将进入老年社会