单项选择题

A.N≥6%;P2O5≥12%;K2O≥40%;总养分≥59%;MgO≥2%
B.N≥6%;P2O5≥12%;K2O≥40%;总养分≥59%;MgO≥1.5%
C.N≥6%;P2O5≥12%;K2O≥40%;总养分≥59%;MgO≥1%
D.N≥6%;P2O5≥12%;K2O≥40%;总养分≥59%;MgO≥0.5%