Which of the Following Statements Is Correct

Which of the following statements is correct?

A) The spin angular momentum of the electron can be directly observed, but the spin magnetic dipole moment cannot be.
B) The spin angular momentum of the electron cannot be directly observed, but the spin magnetic dipole moment can be.
C) Both the spin angular momentum and the spin magnetic dipole moment of the electron can be directly observed.
D) Neither the spin angular momentum nor the spin magnetic dipole moment of the electron can be directly observed.
E) Although both the spin angular momentum and the spin magnetic dipole moment can be defined theoretically, neither has any physical meaning at all.