Here's a problem to solve: Many cars are equipped with a catalytic converter, a device that helps remove hydrocarbons and oxides from car exhaust. As a result, this device helps to

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

- A: increase the production of ozone.
 
- B: decrease the production of smog.
 
- C: increase the emission of nitrogen.
 
- D: decrease the emission of carbon dioxide.
 