In `L-C-R` series `AC` circuit,

Options

A. If `R` is increased, then current will decrease
B. If `L` is increased, then current will decrease
C. If `C` is increased, then current will increase
D. If `C` is increased, then current will decrease

Explanation

To solve the problem regarding the behavior of current in an L-C-R series AC circuit when various components are altered, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Relationship**:
The current \( I \) in an L-C-R series AC circuit is given by the formula:
\[ I = \frac{V}{Z} \]
where \( V \) is the voltage and \( Z \) is the impedance of the circuit.

2. **Impedance Calculation**:
The impedance \( Z \) is defined as:
\[ Z = \sqrt{R^2 + (X_L - X_C)^2} \]
where \( R \) is the resistance, \( X_L = \omega L \) is the inductive reactance, and \( X_C = \frac{1}{\omega C} \) is the capacitive reactance.

3. **Effect of Increasing Resistance \( R \)**:
- If \( R \) is increased, the impedance \( Z \) increases because \( R^2 \) contributes positively to the total impedance.
- As \( Z \) increases, the current \( I \) will decrease since \( I \) is inversely proportional to \( Z \).

4. **Effect of Increasing Inductance \( L \)**:
- If \( L \) is increased, \( X_L \) increases, which can either increase or decrease the total impedance depending on the value of \( X_C \).
- Therefore, the effect on current is not straightforward; it may increase or decrease based on the relative values of \( X_L \) and \( X_C \).

5. **Effect of Increasing Capacitance \( C \)**:
- If \( C \) is increased, \( X_C \) decreases, which can also lead to an increase or decrease in total impedance depending on the values of \( R \) and \( X_L \).
- Thus, the current may increase or decrease.

6. **Conclusion**:
- From the analysis, we can conclude that increasing \( R \) will always decrease the current, while increasing \( L \) or \( C \) does not guarantee a decrease in current. Hence, the correct option is that if \( R \) is increased, the current will decrease.

### Final Answer:
**The correct option is A: If R is increased, then current will decrease.**