王某交付胡某人民币10000元，约定当某股票价格低于10元时，则委托胡某买进该股票，该约定属于()

A、附生效条件的合同

B、附解除条件的合同

C、附生效期限的合同

D、附解除期限的合同

Actually, the date for entry into effect will be 1st February（）.Though the text does not tell us about it.

A.1995

B.1998

C.1999

D.2000