In any CFG $G,$ for every $w \in L(G);$ we have:
The number of parse trees of $w$ = The number of LMDs of $w$ = The number of RMDs of $w$.
i.e. For every string $w \in L(G)$, the number of parse trees is same as the number of leftmost derivations & that is same as the number of rightmost derivations.
For every parse tree, there is a unique leftmost, and a unique rightmost derivation. Similarly, for every leftmost derivation, there is a unique parse tree. Similarly, for every rightmost derivation, there is a unique parse tree.
So, answer is Option B, $l = r = p.$