A car is fitted with a catalytic converter in its exhaust system. When the exhaust gases are analysed, they are found to contain small amounts of nitrogen oxides. Which changes would lead to lower concentrations of nitrogen oxides in the exhaust?
- A1, 2 and 3 are correct
- B1 and 2 only are correct
- C2 and 3 only are correct
- D1 only is correct