Which physical method can separate a mixture of steel ball bearings and marbles?

boiling
evaporation
filtration
sorting

The flowers in a flower arrangement are actually alive

Ibelieve the answer is d

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.