Answer:
c. no reaction happens
Explanation:
Let me take your mind back to the idea of electrode potentials of metals. Remember that the more negative the electrode potential of a metal, the more reducing the metal is. Metals with more negative electrode potentials displace metals with less negative electrode potentials from their aqueous solutions.
The electrode potential of nickel is -0.25 V while that of copper is +0.34 V. Hence, copper is lower than nickel in the activity series and can not displace it from aqueous solution.
This implies that, if a piece of copper metal is placed in a solution that contains nickel(II) ions, no reaction happens .