In the context of deadlock avoidance in a system with multiple instances of resources, the resource allocation graph contains several types of edges:
- **Request edge**: This edge is from a process to a resource, indicating that the process is requesting the resource.
- **Assignment edge**: This edge is from a resource to a process, indicating that the resource has been allocated to the process.
- **Claim edge**: This edge is used in some algorithms (such as the Banker's algorithm) to indicate that a process claims it may request a resource in the future.
However, the **process edge** is not part of the resource allocation graph for deadlock avoidance.
Step 2: Conclusion.
Thus, the correct answer is **(4) Process edge**.