More than a dozen students in that school ______ abroad to study medicine last year. [ ]

A. sent

B. were sent

C. had sent

D. had been sent

某企业有流动资产200万元，其中现金50万元，应收款60万元，有价证券40万元，存货50万元，而其流动负债为150万元。则该企业的速动比率为（）。

A．0.33

B．0.67

C．1

D．1.33