Correct answer:
The sentence which uses an adjective to enrich its meaning is:
The wrinkly elephant lumbered to its water trough.
The adjective used is wrinkly, and it enriches the meaning of the sentence because it gives us more information about the elephant, inviting our imagination to draw this special, perhaps older elephant in our minds.
Wrinkly as an adjective means "very wrinkled" or with a lot of wrinkles; so this word is definitely qualifying the elephant.
We know that elephants usually walk clumsily (lumber), and that they all have wrinkled skins, still, the use of an adjective enhances the idea. If we compare the chosen answer among the other three examples, we can definitely note that there is a great difference between "The elephant", and "The wrinkly elephant".
