Assertion: At a point electric potential is decreasing along x-axis at a rate of `10 V//m`. Therefore, x-component of electric field at this point should be `10 V//m` along x-axis.
Reason: Magnitude of `E_x=(delV)/(delx)`

Options

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

Explanation

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

### Step-by-Step Solution:

1. **Understanding Electric Potential and Electric Field**:
- Electric potential (V) is a scalar quantity that represents the potential energy per unit charge at a point in an electric field.
- The electric field (E) is a vector quantity that represents the force per unit charge experienced by a positive test charge placed in the field.

2. **Relationship Between Electric Field and Electric Potential**:
- The relationship between the electric field and electric potential is given by the equation:
\[ E_x = -\frac{dV}{dx} \]
- Here, \(E_x\) is the x-component of the electric field, and \(\frac{dV}{dx}\) is the rate of change of electric potential with respect to x.

3. **Given Information**:
- The problem states that the electric potential is decreasing along the x-axis at a rate of \(10 \, \text{V/m}\). This means:
\[ \frac{dV}{dx} = -10 \, \text{V/m} \]
- Since the potential is decreasing, the negative sign indicates that as we move in the positive x-direction, the potential decreases.

4. **Calculating the x-component of Electric Field**:
- Using the relationship \(E_x = -\frac{dV}{dx}\):
\[ E_x = -(-10 \, \text{V/m}) = 10 \, \text{V/m} \]
- Therefore, the x-component of the electric field at that point is \(10 \, \text{V/m}\) along the x-axis.

5. **Conclusion**:
- The assertion states that the x-component of the electric field should be \(10 \, \text{V/m}\) along the x-axis, which we have confirmed to be true.
- The reason provided is also true as it correctly describes the relationship between electric field and electric potential.

### Final Answer:
- **Assertion**: True
- **Reason**: True, but it does not correctly explain the assertion.