What is included in the definition of a school bus?

The definition of a school bus specifically includes a multifunction school activity bus, indicating that it is designed for transporting students to and from school as well as to and from school-related activities. This classification emphasizes that school buses are not limited solely to daily commutes but also encompass vehicles used for various educational trips, making option B the most accurate choice.

In contrast, other options suggest broader or different uses. While transporting children might seem relevant, not all vehicles that carry children qualify as school buses under the formal definition, as they may not meet specific safety and design standards. A bus only used for field trips does not encompass the full range of uses assigned to school buses, as it implies a limitation to special occasions rather than regular school operations. Similarly, a vehicle dedicated solely to sports events serves a specific purpose that does not align with the broad definition of a school bus, which is intended for overall school transportation. Therefore, the inclusion of multifunctional capabilities within the definition is what validates option B as the correct answer.