Plug valves operate by:

Plug valves operate by using a simple yet effective mechanism that allows for quick and straightforward control of fluid flow. The correct answer highlights that plug valves can transition from being fully open to completely closed with just a quarter turn of the handle. This quarter-turn operation is a key feature that enables rapid actuation, facilitating efficient management of the flow within pipelines.

This type of valve features a cylindrical or tapered "plug" that fits into a similarly shaped seat within the valve body. When the handle is turned, the plug rotates, either blocking the flow or aligning with the pipeline to allow fluid to pass. This design makes plug valves particularly useful in applications where speed and efficiency in flow control are essential, such as in oil and gas production systems or water treatment facilities.

In contrast, other valve types such as globe valves or ball valves have different operational mechanics and may not provide the same quick action that quarter-turn mechanisms do. Understanding this distinctive feature of plug valves—and their application in various systems—solidifies the rationale for selecting this answer.