EIGRP has no imposed limit on levels of hierarchy, which can be its key design advantage. How is the hierarchy created in an EIGRP network?

by enabling areas in EIGRP to automatically filter routes on border routers

by manually designing the EIGRP network using zones and summarizing at choke points

by using multiple AS numbers and enabling route redistribution between different ASs

by using a hub and spoke design and ensuring that spokes never participate in the EIGRP topology