Scientists think the moon was formed when
a. a large object struck earth, and ejected material from the collision combined.
b. gravitational forces attracted a moon formed elsewhere in space.
c. meteoroids collected and solidified within the pull of earth’s gravity.
d. gases from earth escaped from the atmosphere and condensed in space.

a. a large object struck Earth, and ejected material from the collision combined.

Explanation:

From Giant-impact hypothesis, we understand that Moon was formed when a large object-almost the of the size of Mars collided with the Earth. The impactor is referred to as Theia. The debris ejected from the collision accreted due to gravity and the moon was formed about 4.5 billion years ago in the Hadean eon.

if they have a finite resultant