Which type of amplifier is an RC coupled amplifier that incorporates high-gain transistors or pentodes?

The correct answer is a video amplifier, which is specifically designed to handle high-frequency signals and provide gain for video signals. Video amplifiers utilize RC coupling to achieve the necessary frequency response and performance characteristics required for transmitting video information clearly.

The incorporation of high-gain transistors or pentodes in these amplifiers is crucial, as they help boost the weak video signals while maintaining fidelity. This ensures that the quality of the video output is preserved, which is vital for applications like broadcasting and video transmission.

In contrast, while audio amplifiers are designed to amplify sound frequencies, they typically do not handle the higher frequencies pertinent to video signals. Radio Frequency amplifiers are optimized for even higher frequency signals, such as those used in radio communication, but are not necessarily tailored for video signal integrity. Transconductance amplifiers operate on a different principle, focusing on converting an input voltage to an output current rather than amplifying voltage signals in a video context.

Thus, the characteristics and design of a video amplifier make it the most suitable choice for the function described in the question.