Ans.
Hypothyroidism is a thyroid disorder, in which thyroid gland cannot produce enough thyroid hormones needed by body. It is characterized by weight gain, slow heart rate, and intolerance to cold as thyroid hormone is responsible for increased metabolism and provides heat tolerance.
So, the patient is suffering from hypothyroidism as given symptoms are characteristics of hypothyroidism. Levothyroxine is a medicine, similar to natural thyroid hormones and is used for the treatment of hypothyroidism.
Thus, the correct answer is 'levothyroxine.'