![[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are subjec](http://www.mshxw.com/aiimages/29/602877.png "[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are subjec")
[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are subject to Customs control and a ( ) way bill should be submitted to the Customs by the enterprise providing postal service.
A．cover
B．covering
C．covered
D．having covered
正确答案：B
