I think it is necessary for my 19-year-old son to have his own mobile phone, for I

sometimes want to make sure if he ＿＿ home for dinner. [ ]

A. come        

B. comes      

C. has come        

D. will come

买方代理人和出卖人互相串通，抬高价金，由后者汇给前者一定的回扣，这一行为的性质属于______。

A．欺诈
B．显失公平
C．恶意串通
D．以合法形式掩盖非法目的