If \( R \), \( X_L \), and \( X_C \) represent resistance, inductive reactance and capacitive reactance. Then which of the following is dimensionless:
\( R X_L X_C \)
\( \dfrac{R}{X_L X_C} \)
\( R \dfrac{X_L}{X_C} \)
\( \dfrac{R}{\sqrt{X_L X_C}} \)