Examination of a 56-year-old woman identifies a palpable thyroid mass of relatively fixed position. TSH level is within normal limits. Ultrasound reveals a solid mass of approximately 5 cm in size. Which of the following is the most appropriate next course of action?

A. Watch and wait with rescan in 6 months.
B. Initiate levothyroxine therapy.
C. Refer for fine-needle aspiration biopsy.
D. Refer for radioiodine ablation.