A.500kg/m3B.600kg/m3C.550kg/m3
A.M17.5,M15,M12.5,M10,M7.5,M5 B.M20,M15,M10,M7.5,M5,M2.5 C.M15,M12.5,M10,M7.5,M5,M2.5 D.M20,M15,M12.5,M10,M7.5,M5
A.0 B.5 C.-5 D.10