Here's a problem to solve: Many states require vehicles to be examined and to meet safety and pollution standards. What impact might vehicle inspections have on the environment?

Among the 4 following options, which is the correct answer?

- A: The environment will not be polluted.
 
- B: The environment will become more polluted.
 
- C: Fewer pollutants will be released by vehicles.
 
- D: Fewer pollutants will be produced by older vehicles.
 