Bad Qubits — Learn Quantum by Doing

Multiple choice

By Postulate 2, the possible results of measuring an observable are the eigenvalues of its associated operator. Why must that operator be Hermitian?

Hermiticity guarantees all eigenvalues are real, so the outcomes are real numbers
Hermiticity guarantees the eigenvalues lie on the unit circle
Hermiticity makes the operator its own inverse
Hermiticity forces all eigenvalues to be equal