Sentence Correction

Visitors to the park have often looked up into the leafy canopy and saw monkeys sleeping on the branches, whose arms and legs hang like socks on a clothesline.

(A) saw monkeys sleeping on the branches, whose arms and legs hang
(B) saw monkeys sleeping on the branches, whose arms and legs were hanging
(C) saw monkeys sleeping on the branches, with arms and legs hanging
(D) seen monkeys sleeping on the branches, with arms and legs hanging
(E) seen monkeys sleeping on the branches, whose arms and legs have hung

OA is D.

I have two doubts in this question:
1) According to the OE, "whose" modifies "branches". However, in other official questions I have seen that sometimes the clause modifier doesn't modify the closest noun. Actually, it can modify the main noun in a noun phrase as long as it makes sense and it is not ambiguous.
In this case, we have "monkeys sleeping on the branches, whose..."; "monkeys" is the main noun of that noun phrase and makes sense with "arms and legs hang like socks on a clothesline".
So, my question is: Is the split "whose....", a good reason to eliminate some choices?

2) What are the rules related to a prepositional phrase after a comma? In this question: "..., with arms and legs hanging". How could we know that the prepositional phrase refers to the monkeys and not the visitors. Because these modifiers modify the entire clause, usually modifies the subject (visitors).

Thanks!