Answer
The correct answer is (d).
Work Step by Step
Vanadium has 23 electrons, which is 5 more than Argon. So first the configuration of Argon is completed, then 2 electrons go to the $4s$ orbital, and the remaining 3 electrons go to the $3d$ orbital. Following Pauli's exclusion principle, one electron each fills up in the $3d$ orbital sequentially. This is depicted in option (d).
