The number of d-electrons in Fe2+ (Z = 26) is not equal to that of____________?

The number of d-electrons in Fe2+ (Z = 26) is not equal to that of____________?

A. p-electrons in Ne(Z = 10)
B. s-electrons in Mg(Z = 12)
C. d-electrons in Fe(Z = 26)
D. p-electrons in CI(Z = 17)