Bobbie is always sick and weak       his brother Frank is a good football player, as strong as a horse.

A．when

B．as

C．while

D．though

根据《工程建设项目勘察设计招标投标办法》的规定，招标文件要求投标人提交投标保证金的，保证金数额一般不超过勘察设计费投标报价的( )。

A．1%

B．2%

C．3%

D．4%