Which of the following is not arranged in correct sequence?

The magnetic moment should increase in the proper order, which is ${\mathrm{d}}^1<{\mathrm{d}}^3<{\mathrm{d}}^4<{\mathrm{d}}^5$.

 On the premise that the ligand is a weak field ligand, this is predicated. The pairing won't take place as a result. The magnetic moment rises as the number of unpaired electrons does. So, choice A is unsatisfactory