OG12 100中一个小问题

100. The stars, some of them at tremendous speeds, are in
motion just as the planets are, yet being so far away
from Earth that their apparent positions in the sky do
not change enough for their movement to be observed
during a single human lifetime.
(A) The stars, some of them at tremendous speeds,
are in motion just as the planets are, yet being
(B) Like the planets, the stars are in motion, some
of them at tremendous speeds, but they are
(C) Although like the planets the stars are in motion,
some of them at tremendous speeds, yet
(D) As the planets, the stars are in motion, some of
them at tremendous speeds, but they are
(E) The stars are in motion like the planets, some of
which at tremendous speeds are in motion but
答案中说E subject and verb of the second clause are omitted.
虽说but是连词，但也没必要非得连句子啊。
况且句子主语与前句主语一样。应该可以省略啊
希望能把but后的省略情况解释下吧