The OP-amp can amplify

Answer: Option C

An operational amplifier (OP-amp) is a versatile electronic component designed to amplify a wide range of signals.

Both a.c. and d.c. signals: OP-amps are capable of amplifying both alternating current (a.c.) signals and direct current (d.c.) signals. They can be configured in various ways (e.g., as inverting, non-inverting amplifiers) to handle different types of signals and applications.

a.c. signals only: This is incorrect because OP-amps are not limited to amplifying only a.c. signals.

d.c. signals only: This is also incorrect because OP-amps can amplify both d.c. signals and a.c. signals.

neither a.c. nor d.c. signals: This is incorrect because OP-amps are designed to handle both types of signals.

Thus, Option C: both a.c. and d.c. signals is the correct answer.