Harmonics problem. A square wave of frequency f contains harmonics (sine waves) at f, 3f, 5f, 7f, ... . Suppose a system responds to frequencies in the range 20-40 kHz but is insensitive outside of this range. EXAMPLE:Imagine applying a square wave with f = 30 kHz to this system. What is the shape of the response?[ a 30 kHz sine wave. ]Imagine applying a square wave with f = 10 kHz to this system. What is the shape of the response?A. A 10 kHz sine waveB. A combination of 20, 30 and 40 kHz sine wavesC. A 30 kHz sine waveD. No response