In a series RLC ac circuit, a second resistor is connected in series with the resistor previously in the circuit. As a result of this change, what happens to the impedance of the circuit

* The first thing we observe is that the frequency response does not change

* The current that circulates in the circuit decreases due to the new resistance at the resonance point,

          Z = R + R₂

Explanation:

The impedance of a series circuit is

          Z₀² = R² + (X_L-X_C) ²

when we place another resistor in series the initial resistance impedance changes to

          Z² = (R + R₂) ² + (X_L - X_C) ²

let's analyze this expression

* The first thing we observe is that the frequency response does not change

* The current that circulates in the circuit decreases due to the new resistance at the resonance point,

          Z = R + R₂

scientific laws are the result of testing theories and proving them to be facts.

i think the answer is a, hope this : )