Based on the options provided, let's evaluate each student's proposal:
A. Student's method selected: x (motor vehicles that require fuel combustion)
- This method is likely to increase air pollution rather than reduce it, as burning fuels in motor vehicles releases pollutants.
B. Student's method selected: x (motor vehicles that do not require fuel combustion)
- This method would likely lead to a greater reduction in air pollution because it implies the use of electric vehicles or other forms of transportation that do not rely on burning fossil fuels.
- Added part improvement: The student could consider adding a part that emphasizes the use of renewable energy sources to charge electric vehicles (like solar or wind energy) to further reduce pollutants.
C. Student's method selected: y (increasing purchase of products from far distances transported using fuel-powered vehicles)
- This method is counterproductive as it suggests increasing transportation that relies on fuel combustion, which would increase air pollution rather than reduce it.
Based on the evaluations, Student B's method is the most likely to result in the greatest reduction of air pollution. The added part could be improved further by focusing on renewable energy sources for charging electric vehicles.