A school purposes vehicle is a van or station wagon operating under contract with a school board to carry how many children and/or adults with a developmental disability?

Answer: B — Six or more

A school purposes vehicle is specifically contracted to transport children and/or adults with developmental disabilities. This means that the vehicle must have a larger capacity to accommodate a minimum of six individuals. Option A (five or fewer) and C (ten or more) are incorrect because they do not meet the minimum requirement of six individuals. Option D (twenty or more) is also incorrect because it exceeds the maximum capacity for a school purposes vehicle, which is typically capped at 15 individuals. Therefore, option B (six or more) is the correct answer as it meets the specific requirements for a school purposes vehicle.