Ahomogeneous mixture is also called a solution. an element. a pure substance. a heterogeneous mixture. a compound.

A solution is right answer.

Forgot the question hahaha

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.