# The quantum numbers $\large\frac{1}{2}$ and $-\large\frac{1}{2}$ for the electron spin represents :
$\begin{array}{1 1}(a)\;\text{Rotation of the electron in clockwise and anti clockwise direction respectively}\\(b)\;\text{Rotation of the electron in anti clockwise and clockwise direction respectively}\\(c)\;\text{Magnetic moment of the electron pointing up and down respectively}\\(d)\;\text{Two quantum mechanical states which have no classical analogue}\end{array}$