A chemist produces 460mL of oxygen gas at -43C and constant pressure. To what Celsius temperature must the oxygen be warmed in order for it to have a volume of 600mL?

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.

The answer to this is the 3rd choice!