Answer: C) The rabbit was cornered in a hollow log by a hungry fox.
Explanation:
Well, what does active voice mean? It means that the sentence tells us what the subject of the sentence is doing. Now, all of these sentences tell us movement about a subject, so what makes active voice different?
Active voice is usually in the order of subject, verb, then object. Let us break down the options and see which one applies. Passive voice is the opposite, it goes object, verb, then subject.
✗ - A) The hollow log was often used by animals looking for shelter.
hollow log = object, used by = verb, animals looking for shelter = subject
✗ - B) The deer leaped gracefully over the rabbit and ran into the forest.
The deer = subject, leaped gracefully over = verb, the rabbit = object, and ran into the forest = also a verb
✓ - C) The rabbit was cornered in a hollow log by a hungry fox.
The rabbit = subject, cornered in a hollow log = verb, by a hungry fox = object.
✗ - D) A tremendous leap was performed by the fox as it went over the log.
A tremendous leap = verb, performed by the fox = subject, as it went over the log = object
The answer to your question is option C, "The rabbit was cornered in a hollow log by a hungry fox."