Answer:
The correct answer is calcitonin.
Explanation:
Calcitonin is a hormone produced by the parafollicular cells located in the thyroid. It has a key role in calcium and phosphorus metabolism because it inhibits osteoclasts and also inhibits renal tubular reabsorption of phosphate and calcium. As a result, it allows calcium level to decrease.
In contraposition, the parathyroid hormone (produced by the parathyroid) stimulates osteoclasts and therefore increases blood calcium level.
