______, a man who expresses himself effectively is sure to succeed more rapidly than a man whose command of English is poor.

A．Other things being equal

B．Other things be equal

C．To be equal to other things

D．Other things to be equal

A公司权证的某日收盘价是6元，股票收盘价是24元，行权比例为1。次日A公司股票最多可以上涨或下跌10%，则权证次日的涨跌幅比例为( )。

A．10%
B．40%
C．50%
D．60%