Arrange the orbitals in the order in which they fill and indicate the maximum number of electrons each can hold.

Explanation:

We can fill maximum two electrons in one orbital. The s subshell has 1 orbital that can filled upto two electrons, the p subshell has 3 orbitals that can filled upto six electrons, the d subshell has 5 orbitals that can filled upto ten electrons, the f subshell has 7 orbitals that can filled upto fourteen electrons.

According to the energy level diagram, the 2p, 3p, 4p each can hold 6 electrons because they have 3 orbitals, and 3d, 4d each can hold 10 electrons because they have 5 orbitals, the 5f, 6f, each can hold 14 electrons because they have 7 orbitals. Therefore, the maximum number of electrons would be present in f subshell or 6f orbital.

the answer is option a.