A doctor suspects that her patient may have Grave’s Disease, a thyroid disorder. To be sure, she asks the technician to perform a radionuclide scanning. This procedure requires the use of iodine-131 which, when given in small doses, is used as a medical tracer to detect thyroid disorders. A patient swallows 10 grams of the iodine. Sixteen days later, detectors observe 2.5 grams of iodine in the patient’s thyroid. What is the half-life of iodine-131? A. 8 days

B.16 days

C.32 days