Assertion `:-` An increase in glomerular blood pressure can activate the JG of kidney to release renin.
Reason `:-` Angiotensin I is a powerful vaso constrictor.

Options

A. If both Assertion & Reason are True & the Reason is a correct explanation of the Assertion .
B. If both Assertion & Reason are True but Reason is not a correct explanation of the Assertion
C. If Assertion is True but the Reason is False.
D. If both Assertion & Reason are false.

Answer

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that an increase in glomerular blood pressure activates the juxtaglomerular (JG) cells of the kidney to release renin.
- **Analysis**: In reality, an increase in glomerular blood pressure does not activate the JG cells to release renin. Instead, it is typically a decrease in blood pressure or blood volume that stimulates renin release. Therefore, this assertion is **false**.

2. **Understanding the Reason**: The reason states that angiotensin I is a powerful vasoconstrictor.
- **Analysis**: Angiotensin I is not a powerful vasoconstrictor; it is angiotensin II that has this effect. Angiotensin I is converted from angiotensinogen by renin and then further converted to angiotensin II by the enzyme ACE (Angiotensin-Converting Enzyme). Thus, this reason is also **false**.

3. **Conclusion**: Since both the assertion and the reason are false, we can conclude that the correct answer is that both statements are incorrect.

### Final Answer:
Both the assertion and the reason are false.