Which of the following can cause brake vibrations during application?

Brake vibrations during application are primarily caused by warped rotors. When rotors become warped, typically due to excessive heat, wear, or poor manufacturing, they do not provide a smooth surface for the brake pads to grip against. This uneven contact results in fluctuations in braking force, causing the brake pedal to vibrate and leading to a pulsating sensation that can be felt throughout the vehicle.

In contrast, while uneven tire pressure, low engine oil, and improper wheel alignment can lead to various other handling issues and tire wear, they are not directly responsible for the vibrations felt during brake application. Tyre pressure affects the overall handling and ride comfort, and while it influences vehicle dynamics, it does not specifically cause the brakes to vibrate. Similarly, low engine oil can lead to engine problems but does not impact brake performance, and improper wheel alignment primarily affects steering and tire wear rather than brake function. Therefore, the specific and correct cause of brake vibrations in this scenario is indeed warped rotors.