Wolff-chaikoff effect is -

Ans. is 'c' i.e., Reduced thyroxine synthesis by iodides Iodine and Iodideso Iodine is the fastest acting thyroid inhibitor.o Most important action is inhibition of hormone release (thyroid constipation)\ but all facets of thyroid synthesis may be affected.o Excess iodide inhibits its own transport in thyroid cells and may alter the redox potential of cells, thus interfering iodination - reduced T4/T3 synthesis (Wolff-chaikoff effect).