Which component, when replaced, will change the ride height of a vehicle?

The component that will change the ride height of a vehicle when replaced is the springs. Springs are responsible for supporting the weight of the vehicle, absorbing shocks from the road, and determining the overall ride height. When springs are replaced with new ones that have different stiffness or dimensions, or if they are heavy-duty or lowered versions, this directly affects how high or low the vehicle sits in relation to the ground.

Shocks and struts, while essential for controlling the vehicle's motion and providing stability and comfort, do not alter the ride height on their own. They primarily dampen the oscillations caused by springs and keep the vehicle balanced during movement. Sway bars, or anti-roll bars, are designed to reduce body roll during cornering and do not have any impact on ride height.

Therefore, replacing the springs is the action that will result in a measurable change in the vehicle's ride height, making this the correct choice.