If $R,X_L,\text{ and }{X}_C$ represent resistance, inductive reactance and capacitive reactance. Then which of the following is dimensionless:

The dimensions of  resistance, inductive reactance and capacitive reactance are same 

$\left[{\mathrm{x}}_{\mathrm{L}}\right]=\left[{\mathrm{x}}_{\mathrm{C}}\right]=\left[\mathrm{R}\right]$

From the given options only $\frac{\mathrm{R}}{\sqrt{{\mathrm{X}}_{\mathrm{L}}{\mathrm{X}}_{\mathrm{C}}}}$ will be dimensionless.