Which of the following can lead to reduced vehicle performance if not properly maintained?

Reduced vehicle performance can stem from several system malfunctions or neglecting maintenance. Each of the systems identified plays a critical role in overall vehicle operation.

Brakes are crucial for safety and performance as they are responsible for stopping the vehicle effectively. Worn or improperly maintained brake components can lead to decreased stopping power, longer stopping distances, and overall diminished control of the vehicle.

The suspension system also significantly impacts vehicle performance. It maintains contact between the tires and the road, absorbs shocks from irregularities in the surface, and contributes to handling and ride comfort. If the suspension is not properly maintained, it could lead to poor vehicle handling, increased tire wear, and a less comfortable ride.

The exhaust system affects engine performance and emissions. A properly functioning exhaust allows gases to exit the engine efficiently, helping maintain engine power and fuel efficiency. If the exhaust system is failing or clogged, it could cause back pressure that hinders engine performance and increases harmful emissions.

Given that brakes, suspension, and the exhaust system all have the potential to reduce vehicle performance if maintenance is neglected, it follows that not attending to any of these critical areas can lead to a loss of overall vehicle functionality and safety. Thus, all of the options provided are essential in ensuring optimal vehicle performance.