Which two basic blocks or modules make up the campus architecture? (choose two

Which two basic blocks or modules make up the campus architecture? (choose two.)

A.
core

B.
access-distribution block

C.
services block

D.
network infrastructure

E.
NetFlow

F.
distribution

Explanation:
http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/campover.html#wp708877

Modularity
The second of the two principles of structured design is modularity. The modules of the system are the building blocks that are assembled into the larger campus. The advantage of the modular approach is largely due to the isolation that it can provide. Failures that occur within a module can be isolated from the remainder of the network, providing for both simpler problem detection and higher overall system availability. Network changes, upgrades, or the introduction of new services can be made in a controlled and staged fashion, allowing greater flexibility in the maintenance and operation of the campus network. When a specific module no longer has sufficient capacity or is missing a new function or service, it can be updated or replaced by another module that has the same structural role in the overall hierarchical design. The campus network architecture is based on the use of two basic blocks or modules that are connected together via the core of the network:

Access-distribution block

Services block