There is nothing wrong with using a credit card for purchases. It’s more _______ than carrying loads of cash.

A．convenient

B．valuable

C．sensitive

D．innocent

在发生重大事件或突发性事件时，需要各警种联合作战，但允许各警种和人民警察有权对不属于其职责范围的事项拒绝执行。( )