23.In a previous design, the weight of the discus used in
track competition is concentrated in a metal center,
but now it is lined with lead around the perimeter,
thereby improving stability in flight and resulting in
longer throws.
(A)In a previous design, the weight of the discus
used in track competition is concentrated in a metal center, but now it is
(B)According to a previous design, the weight of
the discus used in track competition was
concentrated in a metal center, but now it is
(C)Once designed with its weight concentrated
in a metal center, the discus used in track
competition is now
(D)The discus used in track competition, once
designed with its weight concentrated in a metal
center, but now
(E)The discus used in track competition was once
designed having its weight concentrated in a
metal center and now
