Answer:to demonstrate why the author used specific ideas, word choices, or writing structures to convey his or her message.
Explanation:
The answer is
“A. The injustice of discrimination.”
The reason for this is that the dog is at old age, stinky and is about to die. And in the book Carlson believes his useless for that reason, and the dog was discriminated for it. The author expressed how society treats (or discriminate) people of old age, person with disabilities and minorities.