单项选择题

A.≥0.5%CH4,≥0.5%CH4,<0.5%CH4
B.≥1.5%CH4,≥1.5%CH4,<1.5%CH4
C.≥1.0%CH4,≥1.0%CH4,<1.0%CH4
D.≥1.5%CH4,≥2.0%CH4,<1.5%CH4