$0.53 A^{\circ }$ is Bohr's radius of the first orbit. In the light of the wave mechanical model, it suggests that 

The number of given orbitals which have electron density along the axis is

${\mathrm{p}}_{\mathrm{x}},{\mathrm{p}}_{\mathrm{y}},{\mathrm{p}}_{\mathrm{z}},{\mathrm{d}}_{\mathrm{xy}},{\mathrm{d}}_{\mathrm{yz}},{\mathrm{d}}_{\mathrm{xz}},{\mathrm{d}}_{\mathrm{z}}^2,{\mathrm{d}}_{{\mathrm{x}}^2-{\mathrm{y}}^2}$

Consider the following pairs of electrons:

(A) (a) $\mathrm{n}=3, \mathrm{l}=1, {\mathrm{m}}_{\mathrm{l}}=1,{\mathrm{m}}_{\mathrm{s}}=+\frac{1}{2}$
(b) $\mathrm{n}=3, \mathrm{l}=2,{\mathrm{m}}_{\mathrm{l}}=1,{\mathrm{m}}_{\mathrm{s}}=+\frac{1}{2}$
(B) (a) $\mathrm{n}=3, \mathrm{l}=2,{\mathrm{m}}_{\mathrm{l}}=-2,{\mathrm{m}}_{\mathrm{s}}=-\frac{1}{2}$
(b) $\mathrm{n}=3, \mathrm{l}=2,{\mathrm{m}}_{\mathrm{l}}=-1,{\mathrm{m}}_{\mathrm{s}}=-\frac{1}{2}$
(C) (a) $\mathrm{n}=4, \mathrm{l}=2,{\mathrm{m}}_{\mathrm{l}}=2,{\mathrm{m}}_{\mathrm{s}}=+\frac{1}{2}$
(b) $\mathrm{n}=3,\mathrm{l}=2,{\mathrm{m}}_{\mathrm{l}}=2,{\mathrm{m}}_{\mathrm{s}}=+\frac{1}{2}$

The pairs of electrons present in degenerate orbitals is/are: