Answer
(a) 0
(b) 0,1
(c) 0,1,2
(d) 0,1,2,3
Work Step by Step
The possible values of $l$ are integers from 0 to $n-1$.
Therefore,
(a) when $n =1$, $0$ is the only possible value of $l$.
(b) $n=2\implies l=0,1$
(c) $n=3\implies l=0,1,2$
(d) $n=4\implies l=0,1,2,3$
