What is "modulation" in the context of signal processing?

A) Changing the signal's frequency

B) Varying a carrier signal's amplitude, frequency, or phase

C) Filtering a signal

D) Sampling a continuous signal

Answer: B) Varying a carrier signal's amplitude, frequency, or phase

Explanation: Modulation is the process of varying one or more properties of a carrier signal (such as amplitude, frequency, or phase) in accordance with a modulating signal, allowing for effective transmission of information.