Final answer:
Vice jaw plates in machining processes are used to protect the workpiece from damage by providing a secure hold without marking or deforming it during operations.
Step-by-step explanation:
In machining processes, the purpose of using vice jaw plates is C) To protect the workpiece from damage whilst being held in the vice. Vice jaws are typically made of softer materials than the workpiece and provide a more secure hold without marking or deforming the workpiece during machining operations. These plates can also be customized with specific features like grooves or protrusions to hold irregularly shaped objects. This helps to ensure that the workpiece remains stable and does not get damaged by the pressure applied by the vice while it is being worked on.