In AC circuits, the impedance \(Z\) is calculated depending on whether the components are resistors, inductors, or capacitors:
- For a circuit containing a resistor and an inductor in series, the impedance is:
\[
Z = \sqrt{R^2 + X_L^2}
\]
- For a circuit containing a resistor and a capacitor in series, the impedance is:
\[
Z = \sqrt{R^2 + X_C^2}
\]
- For a circuit containing only an inductor and a capacitor in series, the impedance is:
\[
Z = |X_L - X_C|
\]
Thus, the correct answer is A, B, and C only.