He had just lost his job when, at the precise moment, his girlfriend broke up with him. She ____ salt into his wound.

A．rubbed

B．had rubbed

C．would rub

D．was rubbing

下列程序段的输出结果是 。
cout ＜ ＜ fixed ＜ ＜ 509.123456789 ＜ ＜ endl;