Adecrease in the amount of a gas in a container may mean a(n) increase in pressure increase in volume decrease in pressure decrease in volume

A decrease in the amount of gas in a container will mean a decrease in pressure.

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.