The Restrictions on the Placing of Electrons in Molecular Orbitals

The restrictions on the placing of electrons in molecular orbitals in molecules and ions

A) must obey the Pauli exclusion principle but not Hund's rule or the Aufbau principle.
B) must obey the Pauli exclusion principle and the Aufbau principle but not Hund's rule.
C) must obey the Aufbau principle but not the Pauli exclusion principle or Hund's rule.
D) are not governed by either the Aufbau principle, Hund's rule, or the Pauli exclusion principle.
E) must obey the Aufbau principle, Hund's rule, and the Pauli exclusion principle.