Which sentence contains a pronoun used as an adjective? 1.she bought the least expensive cage for george, the parakeet.
2.the blue parrot belongs to her.
3. one of the birds is a parakeet.
4. i chose that bird for its bright coloring.

The correct answer should be 4. I chose that bird for its bright coloring.

That can be treated as a pronoun that refers to a specific thing known or understood, which in this case is bird. Here it is a pronoun used as an adjective to describe what bird that is, and the answer is that bird.