Which of the following is a hook up place for locating a plastic gas service?

The correct answer is Tracer Wire. Tracer wire is used in underground utility installations, specifically for locating plastic gas service lines. Since plastic pipes are non-metallic and cannot be detected using traditional locating methods, tracer wire is installed alongside the pipe to provide a means of detection. When a locator device is applied to the tracer wire, it allows personnel to pinpoint the exact location of the plastic gas service for maintenance, repair, or installation purposes.

Other options, while they play roles in gas service systems, do not serve as hook-up points for locating plastic gas services. A farm tap is typically a point where gas is tapped from a high-pressure transmission line to a lower-pressure distribution system and does not pertain to locational tracing. A regulator station manages the pressure of gas flowing through a pipeline and is not intended for locating purposes. Valve assemblies are crucial for controlling the flow of gas but do not help in identification or locating of underground plastic lines.