More than one hundred years ago, students of ornithology reported that hummingbirds can hover as insects flitting gracefully from one flower to another.
A.as insects flitting gracefully from one flower to another
B.like insects flitting gracefully from one flower to another C.as insects do that flit gracefully from one flower to others
D.like insects do that flit gracefully from one flower to others
E.as do insects that flit gracefully from one flower to some other one