This week she turned 13 . She is still a puppy at heart , but her body has slowed down considerably . Her hips bother her and the stairs are difficult to navigate .
According to the above context, choose the best option to answer the following question.
Question: What may be the reason the stairs are hard to navigate .
Options:
A. None of the above choices .
B. The dog is sick .
C. The dog is old .
D. The dog is lazy .


C