The correct answer to the question is:
(b) Frequency-selective circuit
Explanation:
An electrical filter is a circuit designed to allow certain frequencies to pass while attenuating others. It is frequency-selective because it can either allow or block specific frequency ranges, depending on the type of filter (e.g., low-pass, high-pass, band-pass, or band-stop filters). The filter works by manipulating the frequency response of the circuit.
Why not the other options?
- Phase-selective circuit: Although filters can affect the phase of a signal, their primary function is frequency selection, not phase selection.
- Filter-selective circuit: This is not a standard term used in the context of electrical filters.
- None of the mentioned: This would be incorrect because an electrical filter is indeed frequency-selective.
Thus, an electrical filter is a frequency-selective circuit.