Which of the following statements are wrong?
i) Calcination is mainly used for carbonate ore to get its oxide
ii) Hydrated ore and hydroxides become anhydrous by calcination
iii) Impurities like S, As and Sb are removed in the form of elemental vapours by calcination
iv) Roasting is an endothermic process
v) Roasting is mainly applicable for sulphide ore to get its oxide
vi) Some times as a result of roasting, higher oxidation state oxide gets converted into lower oxidation state oxide.

Options

A. only iv is wrong
B. only vi is wrong
C. iii, iv and vi are wrong
D. iv and vi are wrong