Assertion : In series `L-C-R, AC` circuit, current and voltage are in same phase at resonance.
Reason : In series `L-C-R, AC` circuit, resonant frequency does not depend on the value of resistance. Hence, current at resonance does not depend on resistance.

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 both the assertion and the reason provided in the context of a series L-C-R AC circuit.

### Step-by-Step Solution:

1. **Understanding the Assertion**:
- The assertion states that in a series L-C-R AC circuit, current and voltage are in the same phase at resonance.
- At resonance, the inductive reactance (XL) equals the capacitive reactance (XC). This means that the effects of the inductor and capacitor cancel each other out, resulting in the circuit behaving purely resistively.

2. **Analyzing the Phase Relationship**:
- In a series L-C-R circuit, the total impedance (Z) is given by:
\[ Z = \sqrt{R^2 + (X_L - X_C)^2} \]
- At resonance, since \(X_L = X_C\), the impedance simplifies to:
\[ Z = R \]
- This indicates that the current and voltage are in phase, confirming that the assertion is correct.

3. **Understanding the Reason**:
- The reason states that the resonant frequency does not depend on the value of resistance. The resonant frequency (f) is given by:
\[ f = \frac{1}{2\pi\sqrt{LC}} \]
- This formula shows that the resonant frequency depends only on the inductance (L) and capacitance (C), and not on the resistance (R). Therefore, this part of the reason is correct.

4. **Current at Resonance**:
- The current at resonance can be expressed as:
\[ I = \frac{V}{Z} = \frac{V}{R} \]
- This indicates that the current does depend on the resistance (R) since the impedance at resonance is purely resistive (Z = R). Therefore, the statement "current at resonance does not depend on resistance" is incorrect.

5. **Conclusion**:
- The assertion is true: current and voltage are in the same phase at resonance.
- The reason is false: while the resonant frequency does not depend on resistance, the current at resonance does depend on resistance.

### Final Answer:
- Assertion: True
- Reason: False