Pick up the correct statement from the following:
(A) Roasting is not necessary if iron ore is an oxide
(B) Impurities float on the molten iron as slag
(C) The slag contains lime about 45%
(D) All the above
(A) Roasting is not necessary if iron ore is an oxide
(B) Impurities float on the molten iron as slag
(C) The slag contains lime about 45%
(D) All the above