Which of the following has more anti-thyroid action?

Ans. (a) I131Ref: Bailey and Love Principles and Practice of Surgery, 26th edition, Page 758Methods of treating a Thyrotoxic Patient (from Bailey and Love)* Antithyroid Drugs:# Carbimazole is the DOC for preparing the patient to euthyroid state.# It is given in a dose of 10mg three times daily.# Once patient becomes euthyroid: Carbimazole is given a maintenance dose of 5mg three times daily for 6-24 months.# "Block and replacement therapy" - Another method of preparation by giving heavy dose carbimazole and making patient euthyroid and supplementing with 0.1mg thyroxine# Recurrence of thyrotoxic feature is nearly 50%* Surgery:# is around 5% and this has its own risk of surgery.* RAI:# Response is slow but substantial improvement occurs 8-12 weeks.# Two or more doses are required for 20% cases.Choice of treatment in Each case:* Diffuse toxic goiter: Initial dose of anti-thyroid drugs followed by RAI.* Toxic Nodular goiter - Surgery is best, RAI produces lesser response here* Toxic nodule - Surgery or RAI is appropriate* Recurrent thyrotoxicosis after Surgery - Radioiodine is best* Failure of Previous antithyroid drugs or RAI: Surgery is best