A patient is experiencing nervousness, tachycardia, weight loss, and an increase in blood pressure. The patient has a TSH level of 0.1 M IU/mL. The normal TSH level is 0.2-4.8 M IU/mL. The patient has been taking propylthiouracil (PTU) 100 mg tid for a month. What diagnosis does this patient present with?
a. Hypothyroidism
b. Hyperthyroidism
c. Euthyroid