Final answer:
Under the Traffic Safety Act, a commercial vehicle must have a minimum seating capacity of 15 passengers, including the driver, to be classified as a 'bus'.
Step-by-step explanation:
The minimum seating capacity (including the driver) for a commercial vehicle to be considered a 'bus' under the Traffic Safety Act is b) 15 passengers. This classification helps determine regulations regarding vehicle operation, safety standards, and licensing requirements. The definition of a bus in this context does not necessarily align with other definitions used in public transport scheduling or capacity discussions, which often focus on route efficiency and service frequency.