Total harmonic distortion (THD) of a circuit
This circuit only uses linear components. Ideal resistors, capacitors, and inductors are linear components meaning, their behavior is independent of the amplitude of the voltage and current.

As such this circuit is unable to generate harmonics. For that there would need to be a non-linear component present. For example a diode or a transistor.

So the answer is: THD = 0

Obviously this is a question to test your knowledge of the relation between (non) linear circuits and distortion of signals.