We are glad to receive your telegraphic order of May 6 ______ regret that we can- not supply the goods ______ the end of May.

A．but, by

B．and, by

C．but, for

D．and, for

供应商认为采购文件、采购过程和中标、成交结果使自己的权益受到损害的，可以在知道或者应知其权益受到侵害之日起( )个工作日内，以书面形式向采购人提出质疑。

A．10

B．7

C．15

D．45