Assertion :- PTH is a hypercalcemic hormone which increases blood `Ca^(++)` levels.
Reason:- PTH acts on bones and stimulates reabsorption of bone or demineralisation. PTH also stimulate reabsorption of `Ca^(++)` by renal tubules.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Assertion:**
- The assertion states that PTH (Parathyroid Hormone) is a hypercalcemic hormone, which means it increases the levels of calcium ions (Ca²⁺) in the blood.
- This is correct as PTH is secreted by the parathyroid glands and plays a crucial role in regulating calcium levels.

2. **Understanding the Reason:**
- The reason provided states that PTH acts on bones to stimulate the reabsorption of bone or demineralization.
- It also mentions that PTH stimulates the reabsorption of calcium ions by renal tubules.
- This is also correct; PTH promotes the release of calcium from bones into the bloodstream and enhances calcium reabsorption in the kidneys.

3. **Linking Assertion and Reason:**
- The assertion and reason are both correct. The reason explains how PTH increases blood calcium levels by acting on bones and kidneys.
- The process of bone demineralization releases calcium into the blood, and the reabsorption of calcium in the kidneys prevents its loss in urine.

4. **Conclusion:**
- Since both the assertion and reason are true, and the reason correctly explains the assertion, the correct answer is that both the assertion and reason are true, and the reason is the correct explanation of the assertion.

**Final Answer:**
- Assertion and Reason are both true, and the reason correctly explains the assertion.

---