In a spine-and-leaf design, how are leaf and spine switches interconnected?

In a spine-and-leaf architecture, every leaf switch connects to every spine switch. This full-mesh connectivity between the two layers ensures high bandwidth, low latency, and redundancy. If one spine switch fails, traffic can still flow through other spine switches. This design also allows for equal-cost multi-path (ECMP) routing, distributing traffic across all available paths. The incorrect options describe topologies that are either less resilient, create loops without proper STP, or introduce unnecessary intermediate layers, which would negate the benefits of a true spine-and-leaf design.