An "epigram" is usually descried as a bright or witty thought that is tersely and ingeniously expressed.

A．described

B．discarded

C．deserved

D．disconcerted

客户买卖股票时，向经纪人支付股票买卖总额一定比例的现款或股票，其差额由经纪人垫付而进行的股票交易被被称为（）.

A.现货交易

B.期货交易

C.保证金交易

D.期权交易