A 52-year-old woman presents with fatigue, weight gain, constipation and cold intolerance. Blood tests show TSH 18 mU/L (high) and free T4 below the reference range. According to NICE guidance, what is the most appropriate initial management?AReassure and repeat thyroid function tests in 6 monthsBStart Levothyroxine replacement therapyCStart CarbimazoleDNo treatment is required unless TSH exceeds 30 mU/LERefer urgently for thyroid surgeryCheck my answer