单项选择题

A.0.6~1.2m/s;0.6~1.2m/s
B.0.6~1.2m/s;1.0~1.8m/s
C.1.0~1.8m/s;1.0~1.8m/s
D.1.0~1.8m/s;0.6~1.2m/s