The atomic number of an atom is alwaysequal to the number of its. (1) protons, only. (2) neutrons, only. (3) protons plus neutrons. (4) protons plus electrons

You are correct, the atomic number is always equal to the number of protons in the element. It is the relative atomic mass that is equal to the number of protons+neutrons. Electrons have no mass

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.