Which of the Following Is the Central Idea of the Pauli

Which of the following is the central idea of the Pauli exclusion principle?

A) Electrons should have equal principal and magnetic quantum numbers.
B) At least three electrons should exist in a subshell.
C) Electrons have negative charge and positive magnetic polarization.
D) Electrons contain all colors of light.
E) No two electrons in an atom can have the same set of four quantum numbers.