Assertion (A) : The electrostatic energy stored in capacitor plus magnetic energy stored in inductor will always be zero in series `LCR` circuit driven by ac voltage source under condition of resonance.
Reason (R ) : The complete voltage of ac source appears across the resistor in a series `LCR` circuit driven by ac voltage source under condition of resonance.

Options

A. Statement-1 is true, Statement-2: is true, Statement-2 is a correct explanation for Statement-1.
B. Statement-1 is true, Statement-2: is true, Statement-2 is NOT a correct explanation for Statement-1.
C. Statement-1 is true but statement-2 is false
D. Statement-1 is false, Statement-2 is true

Explanation

To solve the question, we need to evaluate the assertion and reason provided in the context of an LCR circuit driven by an AC voltage source under resonance conditions.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that the electrostatic energy stored in the capacitor plus the magnetic energy stored in the inductor will always be zero in a series LCR circuit at resonance.
- The energy stored in a capacitor is given by \( U_C = \frac{1}{2} C V^2 \) and the energy stored in an inductor is given by \( U_L = \frac{1}{2} L I^2 \).
- At resonance, the circuit behaves such that the impedance is minimized and the current reaches its maximum value.

2. **Evaluating the Total Energy**:
- Since both \( C \) (capacitance) and \( L \) (inductance) are positive quantities, and \( V^2 \) and \( I^2 \) are also positive, we can conclude that:
\[ U_C + U_L = \frac{1}{2} C V^2 + \frac{1}{2} L I^2 > 0 \]
- Therefore, the total energy stored in the capacitor and inductor cannot be zero. Thus, the assertion is **false**.

3. **Understanding the Reason (R)**:
- The reason states that the complete voltage of the AC source appears across the resistor in a series LCR circuit under resonance conditions.
- At resonance, the impedance \( Z \) of the circuit is minimized and equals the resistance \( R \). This means that:
\[ Z = R \]
- The voltage across the resistor can be expressed as:
\[ V_R = I \cdot R \]
- Since the current \( I \) is at its maximum value \( I_{max} \), the voltage across the resistor equals the total voltage from the AC source:
\[ V = I_{max} \cdot R \]
- Therefore, the reason is **true**.

4. **Conclusion**:
- The assertion (A) is false, and the reason (R) is true. Thus, the correct answer is that the assertion is false, but the reason is true.

### Final Answer:
- Assertion (A): False
- Reason (R): True