In a three-tier hierarchical campus network design, which action is a design best-practice for the core layer?

A.	provide QoS prioritization services such as marking, queueing, and classification for critical network traffic
B.	provide redundant Layer 3 point-to-point links between the core devices for more predictable and faster convergence
C.	provide advanced network security features such as 802.1X, DHCP snooping, VACLs, and port security
D.	provide redundant aggregation for access layer devices and first-hop redundancy protocols such as VRRP