The correct option is B Parathyroid
Parathyroid gland regulates calcium levels in the body. It produces a hormone called parathyroid hormone (PTH). PTH raises the blood calcium level by bone desorption leading to calcium release when the blood calcium level is too low. Another way that parathyroid hormone works is by increasing the body's ability to absorb calcium from food and also increasing the kidney's ability to hold on to calcium that would otherwise be lost in the urine. , PTH is released to bring the calcium level back to normal. so, the correct answer is option C.