单项选择题
A.one year from the date of issue
B.two years from the date of issue
C.three years from the date of issue
D.four years from the date of issue
单项选择题 The International Oil Pollution Prevention Certificate required by MARPOL is issued to China flag by the （）.
单项选择题 Under the regulations implementing MARPOL, a mobile offshore drilling unit is required to have an International Oil Pollution Prevention (IOPP) certificate when the unit （）.
单项选择题 Convection spreads a fire as a result of （）.