Which of the following reactions are possible?(i) \[\text{Mg+CuS}{{\text{O}}_{\text{4}}}\to \text{MgS}{{\text{O}}_{\text{4}}}\text{+Cu}\](ii) \[\text{Ca+MgS}{{\text{O}}_{\text{4}}}\to \text{CaS}{{\text{O}}_{\text{4}}}\text{+Mg}\](iii) \[\text{Cu+ZnS}{{\text{O}}_{\text{4}}}\to \text{CuS}{{\text{O}}_{\text{4}}}\text{+Zn}\](iv) \[\text{Fe+MgS}{{\text{O}}_{\text{4}}}\to \text{FeS}{{\text{O}}_{\text{4}}}\text{+Mg}\]

• A. (iii) and (iv) only        
• B. (i) and (iv) only
• C. (ii) and (iii) only
• D. (i) and (ii) only