A

Step 1: Understand the definition of reactance.
Reactance is a component of impedance in alternating current (AC) circuits that accounts for the phase difference between the current and voltage. It arises due to inductance (inductive reactance) or capacitance (capacitive reactance).
Step 2: Note the phase relationship.
In reactance, the current and the voltage (electromotive force) are out of phase by π/2 radians (90 degrees). This means that at any instant, when the voltage reaches its maximum value, the current is at zero.
Step 3: Identify the key points.
The total impedance (Z) in an AC circuit can be expressed as Z = R + jX, where R is the resistance, j is the imaginary unit, and X is the reactance. Since reactance corresponds to the imaginary part due to its phase shift of π/2, it confirms the statement in the question.
Therefore, the statement is true and the correct answer is A.