The minimum clear width for an aisle access way not required to be accessible in a Group M occupancy must be _____ inches.

In a Group M occupancy, which typically includes mercantile spaces like retail stores, the minimum clear width for an aisle access way that is not required to be accessible is set for efficient movement and safety. The correct answer of 30 inches provides adequate space for individuals to navigate aisles, accommodating the movement of merchandise and patrons without creating congestion. This width allows for sufficient passage while also considering factors such as shelving and displays that may be present in a mercantile environment.

Options that suggest widths less than 30 inches, such as 24 inches, could potentially lead to crowding and impede movement, especially in busy retail settings. Wider widths, like 32 or 40 inches, while ensuring even more ease of movement, are not necessary per the specific requirements for non-accessible aisles in Group M occupancies. Therefore, 30 inches is the minimum width specified, balancing accessibility considerations with the practical layout of commercial spaces.