There are four stations in the laboratory in which students are measuring the densities of different objects. Data for each object is given below which station contains the object with the largest density

Any photo? or something

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.