prep一道语法题

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