What are two valid scaling techniques when an EIGRP network is designed that consists of more than 1000 routers? (Choose two.)

What are two valid scaling techniques when an EIGRP network is designed that consists of more than 1000 routers? (Choose two.)
A . Use structured hierarchical topology with route summarization
B . Used sub-second timers
C . Use the distribute-list command to filter routes
D . Modify delay parameters on the links
E . Implement multiple EIGRP autonomous systems

Answer: A,E