What are the values of the orbital angular momentum of an electron in the orbitals $1s,3s,3d$ and $2p$?

Orbital angular momentum of an electron $=\sqrt{1(1+1)}h$

$1=0⟹s$ orbital

For 1s, 3s it is 0 

$1=1⟹p$ orbital

For 2p it is $\sqrt{2}\mathrm{h}$

$1=2⟹d$ orbital

For 3d it is $\sqrt{6}\mathrm{h}$

$L=\sqrt{l(l+1)}\cdot \frac{h}{2\pi }=\sqrt{l(l+1)}\cdot ħ$

Hence, the option A is correct.