Which of the Following Spin Functions Represents a Valid Spin $\alpha$

Which of the following spin functions represents a valid spin wavefunction for two paired electrons?

A) $\alpha$ (1) $\alpha$ (2)
B) $\beta$ (1) $\beta$ (2)
C) $\alpha$ (1) $\beta$ (2) + $\beta$ (1) $\alpha$ (2)
D) $\alpha$ (1) $\beta$ (2) - $\beta$ (1) $\alpha$ (2)