When he was doing the software development project, he ___________ many problems that he had to solve on his own.

A．came up with

B．came through

C．came across

D．came out

某投资者以贴现形式购买了一张面值1000元，期限为3年的可提前赎回债券，市场上同期限、同面值并且其他条件与上述可提前赎回债券完全一致的普通债券的购买价格为950元，则上述可提前赎回债券的购买价格可能为( )。

A．1000元

B．950元

C．930元

D．900元

E．890元