Refer to the exhibit. Which recommended practice is applicable?（）

• A、If no core layer is deployed, the design will be easier to scale.
• B、If no core layer is deployed, there will be fewer cabling requirements.
• C、If no core layer is deployed, the distribution switches should not be fully meshed.
• D、A dedicated campus core layer is not needed for connecting fewer than five buildings.
• E、A dedicated campus core layer should be deployed for connecting three or more buildings.