Read the following context and answer the question.
Context: I held him , gazing into his glazed eyes , telling him I loved him , as the vet administered the shot . We were nervous when the German Shepherd puppy wandered up to our property the next year , not sure how Charly would react to him . But Charly adopted him and now , even though Max is twice Charly 's size , Charly still treats him like his baby . And Max lets him .
Question: What may be the reason why the vet administered the shot ?
Answer:


None of the above choices .