A Band-Pass Filter, which filters out the low and high frequencies.
You can try and calculate the resonant frequency (maximum in this case).
At resonance inductor cancels the effect of capacitor, so X(L)=-X(C), therefore, wL=1/(wC),
then w=1/[sqrt(LC)],
and since w=2Pi*f:
f(resonant)=1/[2Pi*sqrt(LC)]
You can set freq of the AC supply to resonant and see that it, indeed, is the maximum in this case.
I got 2.32 MHz.
