Which medication is used to treat hyperthyroidism?

A. Propylthiouracil (Propacil): This medication inhibits thyroid hormone synthesis and peripheral conversion of T4 to T3 and is used to treat hyperthyroidism. B. Liotrix (Thyrolar): A combination thyroid hormone replacement (T4/T3) used for hypothyroidism, not to treat hyperthyroidism. C. Levothyroxine (Synthroid): Synthetic T4 used to replace thyroid hormone in hypothyroidism, not for hyperthyroidism. D. Liothyronine (Cytomel): Synthetic T3 for hypothyroid replacement or specific indications, not used to reduce thyroid activity.