England has many rivers, _____ are very long and wide. [ ]

A. none of which

B. all of them

C. every one of them

D. neither of which

下列叙述中，( )违反了安全监督检查人员的义务。

A．要求被审查、验收的单位购买指定产品

B．监督检查时出示有效的监督执法证件

C．遵循忠于职守的原则

D．秉公执法