-4. In computer r architecture, cache coherence is the uniformity of shared resource data that ends up stored in multiple local caches. When clients in a resource, problems may arise with incoherent data. Discuss how the problem of maintaining coherence of cached data manifests itself in the following processing environments: 1) A Single processor system; 2) Multiprocessor systems; and 3) Distributed systems- system maintain caches of a common memory