In AC circuits, reactance depends on frequency. According to the sources, inductive reactance is $X_L = \omega L$ and capacitive reactance is $X_C = 1/(\omega C)$ . At very high frequencies ($\omega \to \infty$), $X_L$ becomes infinitely large, causing inductors to act as open circuits. Meanwhile, $X_C$ approaches zero, causing capacitors to act as short circuits (wires). For the circuit provided in the NEET 2023 (Manipur) exam, these conditions effectively remove the branch containing the inductor and treat the capacitor branch as a purely resistive path. The resulting combination of remaining resistors yields a total effective impedance of 3 $\Omega$.