Straight D,
By absorbing the nutrition from the new leaves of the margosa tree, root growth is hampered by the agelbop, causing the edge of leaves to weaken from stiff to loose and droop down earlier than usual.
(A) root growth is hampered by the agelbop, causing the edge of leaves to weaken from stiff to loose and droop down
root growth does not absorb nutrition agelbop does.(B) root growth is hampered by the woolly agelbop, and this causes the edge of leaves points to weaken from stiff to loose , and their drooping down
root growth does not absorb nutrition agelbop does.(C) the woolly agelbop hampered root growth, which causes the edge of leaves to weaken from stiff to loose, and drooping down
root growth does not causes the edges of leaves to weaken.(D) the woolly agelbop hampered root growth, causing the edge of leaves to weaken from stiff to loose and to droop downCorrect, the agelbop hampered root growth and this in turn caused edge of leaves to weaken.(E) the woolly agelbop hampered root growth, and this causes the edge of leaves to weaken from stiff to loose, and their drooping down
and eliminates causal relationship, a verb-ing modifier is needed here.