Bowls X and Y each contained exactly 2 jelly beans, each of which was either red or black, One of the jelly beans in bowl X was exchanged with one of the jelly beans in bowl Y. After the exchange, were both of the jelly beans in bowl X black ？（）
(1)Before the exchange, bowl X Contained 2 black jelly beans.
(2)After the exchange, bowl Y contained 1 jelly bean of each color.

A．条件(1)充分，但条件(2)不充分．

B．条件(2)充分，但条件(1)不充分．

C．条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．

D．条件(1)充分，条件(2)也充分．

E．条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

交易双方信息不对称，比方说买方不清楚卖方一些情况，是由于( )。

A．卖方故意要隐瞒自己一些情况

B．买方认识能力有限

C．完全掌握情况所费成本太高

D．以上三种情况都有可能