A gas water heater is being installed in an alcove. According to the 2022 CPC, what is the exception to the requirement for combustion air openings when the alcove opens into a room?

• A mechanical ventilation system can substitute for combustion air openings
• No combustion air openings are required if the alcove is less than 50 cubic feet
• The room can be considered the air supply if the door is undercut at least 1 inch above the floor
• Combustion air can be taken from an adjacent attic space