Q.
A. Mn2+ < Fe2+ < Co2+ < Ni2+
B. Ni2+ < Co2+ < Fe2+ < Mn2+
C. Fe2+ < Mn2+ < Ni2+ < Co2+
D. Co2+ < Mn2+ < Fe2+ < Ni2+
E. None of the above
Correct choice: A
Explanation: