According to NFPA 101, Life Safety Code, interior finish requirements are based on occupancy type, location within the building, and the presence of automatic sprinklers. For a new educational occupancy, the most stringent requirements apply to the means of egress. Exits, such as enclosed stairways and exit passageways, must have an interior wall and ceiling finish meeting Class A criteria. Class A materials have the lowest flame spread and smoke development ratings, providing the highest level of safety in these critical evacuation routes. The absence of a sprinkler system means this base requirement cannot be relaxed.

B. Class B: This class is permitted for exit access corridors in new educational occupancies, but not for the more protected exit enclosures themselves.

C. Class C: This class is generally permitted only in individual rooms and other spaces that are not part of the primary means of egress system.

D. Class A, B, or C: This is incorrect because NFPA 101 specifies distinct finish classes for different areas; only Class A is permitted for exits in this scenario.

1. NFPA 101®, Life Safety Code®, 2021 Edition. Chapter 14, "New Educational Occupancies," Section 14.3.3.1, which states, "Interior finish shall be in accordance with Section 10.2."

2. NFPA 101®, Life Safety Code®, 2021 Edition. Chapter 10, "Interior Finish, Contents, and Furnishings," Table 10.2.2.1.1, "Interior Wall and Ceiling Finish Requirements by Occupancy." The table specifies a Class A finish for "Exit Enclosures" in "New Educational" occupancies.

3. Kirk's Fire Investigation, 8th Edition. Chapter 10, "Building Construction." This text often discusses the role of interior finishes and their classification (Class A, B, C) based on ASTM E84 testing in relation to building and life safety codes like NFPA 101. It reinforces that exits require the highest-rated materials for life safety. (e.g., Section on "Interior Finishes and Their Role in Fire Spread").