A mesh configuration provides the greatest fault tolerance. ISACA’s glossary explicitly defines mesh topology as “a fault-tolerant topology in which network nodes and endpoints are mostly, if not fully, interconnected.” That directly answers the question.

Option D is correct because a mesh topology provides multiple alternate communication paths. If one link or node fails, traffic can often be rerouted through other paths, making the network more resilient than star, ring, or bus topologies.

Option A is less fault tolerant because the central hub or switch can become a single point of failure.

Option B is less fault tolerant because failure in the ring can disrupt communication unless specialized redundancy exists.

Option C is the least fault tolerant among these common topologies because the shared backbone can become a major single point of failure.

Therefore, D is the best answer, and ISACA’s glossary directly supports it.

References (Official ISACA):

ISACA Glossary, Mesh topology — “A fault-tolerant topology...”