Magnetism emanates from the flow of current in a closed loop due to the orbital movement of the electron or the orbital magnetic moment of an electron.

The magnetic moment of an electron (Bohr magneton) is formulated by, I is the orbital electron in an atom, is the radius of the revolution of the electron from the center. Similarly, the Spin magnetic moment is formed due to the spin of the electron, S is the spin quantum number is the mass of electron, e is the charge spark.

Now as for the other options, Pauli Exclusion Principle is a part of quantum mechanics, which states that a minimum of only two electrons can occupy the same orbital and electrons must have opposite spin, the principle states the condition of magnetic moment not its origin. The polar nature of the molecule is very different on the other hand has no connection with the origin of the magnetism it only states polarity between molecules.