使用L/C、D/P和D/A三种支付方式结算货款，就卖方的收汇风险而言，从小到大依次排序为( )。

A．D/P、D/A和L/C

B．D/A、D/P和L/C

C．L/C、D/P和D/A

D．L/C、D/A和D/P

Control of fire on a ship should be addressed（）.

A.immediately after restoring vital services

B.immediately

C.following control of flooding

D.following establishment of fire boundaries