Assertion: At depth h below the water surface pressure is `p`. Then at depth `2h` pressure will be `2p`. (Ignore density variation).
Reason: With depth pressure increases linearly.

Options

A. If both Assertion and Reason are true and the Reason is correct explanation of the Assertion.
B. If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
C. If Assertion is true, but the Reason is false.
D. If Assertion is false but the Reason is true.

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

### Step-by-Step Solution:

1. **Understanding Pressure at Depth**:
The pressure at a depth \( h \) in a fluid is given by the formula:
\[ P = P_0 + \rho g h \]
where:
- \( P_0 \) is the atmospheric pressure at the surface,
- \( \rho \) is the density of the fluid,
- \( g \) is the acceleration due to gravity,
- \( h \) is the depth.

2. **Pressure at Depth \( h \)**:
According to the assertion, at depth \( h \), the pressure is \( p \). Therefore, we can write:
\[ p = P_0 + \rho g h \]

3. **Pressure at Depth \( 2h \)**:
Now, we need to find the pressure at depth \( 2h \):
\[ P(2h) = P_0 + \rho g (2h) = P_0 + 2\rho g h \]

4. **Relating Pressures**:
We already know from step 2 that:
\[ P_0 + \rho g h = p \]
Therefore, we can substitute \( P_0 \) from this equation into the pressure at \( 2h \):
\[ P(2h) = (p - \rho g h) + 2\rho g h = p + \rho g h \]

5. **Conclusion**:
From the above equation, we see that:
\[ P(2h) = p + \rho g h \neq 2p \]
Thus, the assertion that the pressure at depth \( 2h \) is \( 2p \) is incorrect.

6. **Evaluating the Reason**:
The reason states that pressure increases linearly with depth. This is true because the pressure increases by a constant amount \( \rho g \) for each unit increase in depth. Therefore, the reason is correct.

### Final Answer:
- The assertion is **false**.
- The reason is **true**.