Explanation

(c)
${CuSO}_{4}$will react with elements placed above it in electrochemical series and it would not react with elements places below it in electrochemical series.
∴ ${CuSO}_{4}$ reacts with Zn and Fe placed above it.
${CuSO}_{4}$ + Fe → ${FeSO}_{4}\$ + Cu
${CuSO}_{4}$ + Zn → ${ZnSO}_{4}$ + Cu
∴ ${CuSO}_{4}$ does not react with Ag, placed below it.
${CuSO}_{4}$ + Ag → no reaction.