A 35-year-old woman presents with fatigue, weight gain, cold intolerance and constipation. Her TSH is 18 mIU/L (elevated) and free T4 is low. According to Canadian thyroid guidelines, what is the most appropriate initial management?AObserve and repeat thyroid function tests in 6 monthsBStart levothyroxine replacement aiming for normal TSHCStart liothyronine (T3) monotherapyDStart combination T3/T4 therapy for faster symptom reliefEStart iodine supplementation aloneCheck my answer