Which of the following a true statements regarding the use of VLANs to segment anetwork? （）

• A、They increase the size of collision domains
• B、They allow logical grouping of users by function.
• C、They can enhance network security.
• D、They increase the size of the broadcast domain while decreasing the number of collision domains.
• E、They increase the number of broadcast domains while decreasing the size of the broadcast domains.
• F、They simplify switch administration.