Answer:
C. His body is producing too much of the thyroid hormone.
Step-by-step explanation:
Hyperthyroidism is a condition where the thyroid gland produces an excessive amount of thyroid hormone called thyroxine. Symptoms of hyperthyroidism in dogs can include increased thirst, vomiting, and diarrhea. This occurs due to the excessive amount of thyroxine in the bloodstream. Therefore, option C, "His body is producing too much of the thyroid hormone", best describes Fatima’s pet's condition.