Moyan has won the Noble Prize in Literature, which has made him world-famous, but before that no one could have imagined how great a role he _______ in the literary world.

A．had played

B．has played

C．is playing

D．was to play

金融期权交易最早始于（）。

A.股票期权

B.利率期权

C.外汇期权

D.股票价格指数期权