Correct answer: C. It filters exhaust gases and reduces air pollution.
The purpose of a catalytic converter (CAT) is to remove toxic or polluting gases such as carbon monoxide, nitrogen oxide and unburned hydrocarbons from the exhaust emissions. When the CAT is faulty, an engine management warning light illuminates on the dashboard and drivers should seek advice from a competent person.
This is an official-style question from the Safe and Responsible Driving topic of the Ireland driver theory test (Cat. B). Practise all 804 questions free on iTest.ie — with timed mock exams, automatic mistake tracking and progress sync across devices.
Practise the full question bank free →