The nurse practitioner is working up a patient suspected of being hypothyroid. Which of the following findings is consistent with hypothyroidism?

a. Elevated serum thyroid-stimulating hormone (TSH)
b. Elevated serum free thyroxine (T4)
c. Elevated triiodothyronine (T3)
d. Serum concentration of thyroid peroxidase (TPO)
d. Autoantibodies within normal range