---Has Tom finished his composition yet?

　 ---I have no idea, he _____ it this morning.

A．would write 　　

B．has written 　　

C．wrote

D．was writing

某优先股面值1000元，发行价格1100元，发行成本4%，每年付息一次，固定股息率6%，所得税税率为33%，则优先股的税前资金成本为（）。

A．7%

B．8%

C．8.44%

D．8.56%