What can lead to a breakdown concerning power steering?

A breakdown concerning power steering can occur due to a broken power steering cylinder because this component is essential for the hydraulic system that assists in steering. The power steering cylinder helps to amplify the force exerted by the driver on the steering wheel, allowing for easier maneuverability of the vehicle. If the cylinder is broken, it would compromise the hydraulic pressure necessary for the system to operate effectively, potentially leading to complete power steering failure.

The other options, while they can affect vehicle operation, do not directly relate to power steering functionality. Low tire pressure primarily impacts traction and vehicle stability, leaking oil can contribute to numerous engine and mechanical issues but isn't directly linked to power steering, and faulty headlights primarily affect visibility rather than steering control. Therefore, the broken power steering cylinder stands out as the most relevant cause of a power steering breakdown.