Pick up the correct specification of one-room quarters generally adopted from the following:$?

• A. Six quarters in a row
• B. The size of room is either 3.5 m ‚àö√≥ 3 m or 4.2 m ‚àö√≥ 2.5 m
• C. The front verandah is kept 2 m wide
• D. All the above