Answer the following question given this paragraph: 

Catalytic converters are used on motor vehicles. They break down pollutants in exhaust to non-toxic compounds. For example, they change nitrogen oxides to harmless nitrogen and oxygen gases.


Q: Catalytic converters used on motor vehicles break down pollutants in what, yielding non-toxic compounds?

 Choices:

- muffler

- intake

- oil

- exhaust

A:
exhaust
