The orbital angular momentum for an electron resolving in an orbit is $\large\frac{h}{2\pi}$$\sqrt{l(l+1)}$.This momentum of a $s$-electron is :

Question

$\begin{array}{1 1}(a)\;\large\frac{h}{2\pi}&(b)\;\sqrt{2}\large\frac{h}{2\pi}\\(c)\;\pm \large\frac{1}{2}\frac{h}{2\pi}&(d)\;zero\end{array}$