Every possible means ____, but none ____ successful．

A．has tried; has proved

B．tried; proves

C．has been tried; proves

D．is being tried; is proved

在卸货港，承运人回收（），向提单上注明的收货人或提单受让人交付货物后，其交付货物的责任即告终。

A.一份正本提单

B.一套正本和一份副本提单

C.全套正本提单

D.一份正本和全套副本提单