We have been good friends ____ we joined the same ping-pong team. [ ]

A. after

B. before

C. since

D. until

手机到手机转账功能，转账时无需知道收款方的银行账号，只需输入收款方手机号码和转账金额即可轻松实现建设银行同城和异地账户之间的转账，是建设银行手机银行首创的功能。