股票期权的行使方法包括( )。

A．现金行权

B．委托行权

C．账户支付

D．无现金行权

E．无现金行权并出售

A rigid lifesaving device only designed for survivors to hold on to while in the water is a（）.

A.liferaft

B.life float

C.life preserver

D.buoyant apparatus