Assertion : When an ideal fluid flows through a pipe of non-uniform cross-section, then pressure is more at that section where area is more if the pipe is horizontal.
Reason : According to Bernoulli's theorem speed at broader cross-section will be less.

Options

A. If both Assertion and Reason are correct 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 Assertion is false but Reason is true.

Answer

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

### Step 1: Understand the Assertion
The assertion states that when an ideal fluid flows through a pipe of non-uniform cross-section, the pressure is greater at the section where the area is larger, provided the pipe is horizontal.

**Explanation**: According to Bernoulli's theorem, for an ideal fluid flowing through a horizontal pipe, the sum of pressure energy, kinetic energy, and potential energy per unit volume remains constant. In a broader section of the pipe, the area is larger, which means the fluid moves slower. Since the kinetic energy (related to speed) is lower in this section, the pressure must be higher to maintain the energy balance.

### Step 2: Understand the Reason
The reason states that according to Bernoulli's theorem, the speed at the broader cross-section will be less.

**Explanation**: This statement is true; however, it is not the correct explanation for the assertion. The relationship between speed and area is actually derived from the equation of continuity, which states that for an incompressible fluid, the product of the cross-sectional area and the fluid velocity must remain constant. Therefore, if the area increases, the velocity must decrease.

### Step 3: Determine the Truth of Assertion and Reason
- The assertion is **true**: Pressure is indeed higher in the broader section of the pipe.
- The reason is **true**: The speed is less at the broader section, but it is not explained by Bernoulli's theorem; it is explained by the equation of continuity.

### Conclusion
Given the analysis:
- The assertion is true.
- The reason is true but does not correctly explain the assertion.

Therefore, the correct answer is option **C**: Assertion is true, but reason is false.