The correct answer is: C. is defined with respect to a point on the machine.
A coordinate system is a system for assigning unique identifiers to points in space by using a set of numbers, typically called coordinates. The order of the coordinates and the units in which they are measured vary according to the coordinate system and application.
In the context of manufacturing, a coordinate system is used to describe the location of points on a workpiece. The coordinate system is typically defined with respect to a point on the machine, such as the center of the spindle. This allows the machine to accurately position the cutting tool relative to the workpiece.
Option A is incorrect because the coordinate system can be two-dimensional or three-dimensional, depending on the application.
Option B is incorrect because the coordinate system does not change from part to part. It is defined once for the machine and remains the same for all parts that are machined on the machine.
Option D is incorrect because not all of the above are true. Option A is not true, and Option B is not true.
Option E is incorrect because the correct answer is Option C.