Which ranks the solutions in order of greatest to least solubility? X → Y → Z

Y → X → Z

Z → X → Y

Y → Z → X

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.