关于伴随状语的两道OG题目

39. For members of the seventeenth-century Ashanti nation in Africa, animal-hide shields with wooden frames were essential items of military equipment, a method to protect warriors against enemy arrows and spears.
(A) a method to protect
(B) as a method protecting
(C) protecting
(D) as a protection of
(E) to protect
选C

49. The cameras of the Voyager II spacecraft detected six small, previously unseen moons circling Uranus, which doubles to twelve the number of satellites now known as orbiting the distant planet
(A) which doubles to twelve the number of satellites now known as orbiting
(B) doubling to twelve the number of satellites now known to orbit
(C) which doubles to twelve the number of satellites now known in orbit around
(D) doubling to twelve the number of satellites now known as orbiting
(E) which doubles to twelve the number of satellites now known that orbit

选B

都是伴随状语的情况么？怎么第一题doing的主语是主句的主语，而第二道题是整个主句呢？这两种方式都可以做伴随状语doing的主语么？请赐教！

第一题是伴随的情况 主语是主句主语

第二题是因为which无法指代之前的证据句子 只有ING可行