The last orbit of argon would have how many electrons?

The maximum number of electrons in a subshell is given by the expression:

Which one of the following sets of quantum numbers is incorrect?

Principal quantum number $(n)$	Azimuthal quantum number $(l)$	Magnetic quantum number $(m)$

Given below are two statements :
Statement $I$ : $A$ spectral line will be observed for a $2p_x \rightarrow 2p_y$ transition.
Statement $II$ : $2p_x$ and $2p_y$ are degenerate orbitals.
In the light of the above statements,choose the correct answer from the options given below :

Describe the orbitals with the following quantum numbers using $s, p, d, f$ notation:
$(a) n = 1, l = 0$
$(b) n = 3, l = 1$
$(c) n = 4, l = 2$
$(d) n = 4, l = 3$

Which quantum number determines the shape of the subshell?