The correct option is D silver
CuSO4 will react with elements placed above it in electrochemical
series and it would not react with elements placed below it in
electrochemical servies.
CuSO4 reacts with Zn and Fe placed above it
CuSO4+Fe→FeSO4+Cu
CuSO4+Zn→ZnSO4+Cu
∴CuSO4 doesnot react with Ag, placed below it.
CuSO4+Ag⟶ no reaction.