A production facility that requires its air to be free of particulate matter requires staff and visitors to enter the production floor by way of a single hallway that is interrupted at each of three points by a changing room. In each room, an entrant must change into a new lab jacket, a hat, and new clean shoe coverings after the room is blasted with air. The facility intends to speed up the process of entering the production facility by replacing the three rooms with two changing rooms of a new design whose method of blasting air is effective enough to maintain the required air quality.
Which of the following