单项选择题
A.纯磁铁矿石 B.磁铁矿石 C.假象赤铁矿 D.半假象赤铁矿
A.64.2% B.72.4% C.80.2%
A.(1)〉(2)〉(3)〉(4) B.(3)〉(1)〉(2)〉(4) C.(1)〉(3)〉(2)〉(4) D.(2)〉(3)〉(4)〉(1)