Ⅱ类的决断高是多少？ What is the DH for CAT Ⅱ?
A.低于60米但不低于30米。below 60m but not below 30m
B.低于45米但不低于30米。below 45m but not below 30m
C.低于100米但不低于60米。below 100m but not below 60m
正确答案是1