Which of the valves listed can best be used for throttling?

The globe valve is considered the best option for throttling due to its design and function. Unlike other types of valves, globe valves have a spherical body with an internal baffle that provides a significant amount of resistance to flow, allowing for precise control of fluid flow rates. This design enables operators to make fine adjustments to the flow, which is crucial in throttling applications where maintaining a specific flow rate is important.

Globe valves are engineered to handle varying pressure drops and can efficiently manage flow direction and turbulence, making them ideal for applications requiring varying degrees of fluid flow. This quality distinguishes them from gate valves, which are primarily designed for on/off service and not suitable for throttling, as they do not provide adequate control over flow rates.

While both plug cocks and butterfly valves can be used for throttling to some extent, they do not offer the same level of precision and flexibility as globe valves. The shape and internal design of a globe valve make it effective for applications where precise flow control is crucial. Thus, the ability to perform well under throttling conditions solidifies the globe valve as the optimal choice for this purpose.