Final answer:
The correct answer is the Allocation graph, known as the Resource Allocation Graph (RAG), which represents system states of resources and processes.
Step-by-step explanation:
The directed graph that depicts a state of the system of resources and processes, where each process and each resource is represented by a node, is known as the Resource Allocation Graph (RAG). Option B) Allocation graph is the correct answer. In such a graph, nodes represent both processes and resources, while edges indicate the allocation and request of resources by the processes. An allocation graph can be used to detect the presence of deadlocks in a system by looking for cycles. If a cycle exists, it may mean that a set of processes is in a deadlock state, where each process in the set is waiting for a resource held by another process in the set.