For principal quantum number n = 4, the total number of orbitals having $\mathcal{l}$ = 3 is

$\because \mathrm{n}=4,\therefore \mathrm{l}=0,1,2,3,\mathrm{i},\mathrm{e}.,4\mathrm{s},4\mathrm{p},4\mathrm{d}$ and 4f subshell.

$\text{ But }\mathrm{l}=3\text{ is only for }\mathrm{f}\text{-subshell which has }7\text{ orbitals. }$