The correct answer is C. The graph labeled C in the illustration represents a bandpass filter. A bandpass filter is a type of filter that allows signals within a certain frequency range to pass through while attenuating signals outside that range. This is the defining characteristic of a bandpass filter, and the graph in option C clearly shows this frequency-selective behavior. The other options do not depict a bandpass filter. Option A shows a lowpass filter, Option B shows a highpass filter, and Option D shows a notch filter, which is a different type of frequency-selective filter.