![[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are ( )](http://www.mshxw.com/aiimages/29/603077.png "[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are ( )")
[单项选择题] The loading, unloading, transshipment and transit of inward and outward mail bags are ( ) Customs control and a covering way bill should be submitted to the Customs by the enterprise providing postal service.
A．subject to
B．upon
C．into
D．with
正确答案：A
