单项选择题
A.the purpose of trimming
B.the approval for ballast
C.the purpose of voyage
D.the approval for operation
单项选择题 The load line certificate is issued by（）.
单项选择题 The Immigration and Naturalization Service is concerned with which document on a vessel making preliminary entry into a U.S. port from a foreign port?（）.
单项选择题 The granting of radio pratique （）the vessel only as far as the Port Officer of Health is concerned．