单项选择题

A.颗粒物≤20mg/m3,二氧化硫≤400mg/m3,氟化物≤3mg/m3
B.颗粒物≤30mg/m3,二氧化硫≤200mg/m3,氟化物≤3mg/m3
C.颗粒物≤30mg/m3,二氧化硫≤400mg/m3,氟化物≤3mg/m3