What is the primary purpose of multiplexing networks?

The primary purpose of multiplexing networks is to combine multiple circuits into a single link. This process allows multiple signals or data streams to be transmitted simultaneously over a single physical medium, which maximizes the usage of the available bandwidth. By integrating multiple data flows into one connection, multiplexing significantly optimizes network resources and infrastructure, reducing the need for additional physical circuits.

For example, in telecommunications, this is used to enable voice, video, and data services to coexist on the same line, all while maintaining the integrity and speed of each service. This efficient sharing of capacity is vital in modern communications, where bandwidth can be a limiting factor.

The other options focus on different aspects of communication. While reducing the number of circuits can be a benefit of multiplexing, its fundamental role is about combining circuits, making the correct choice the best representation of multiplexing's primary function.