What are struts primarily used for in a vehicle?

Struts play a crucial role in a vehicle's suspension system, primarily serving to provide structural support and absorb shock during driving. They are designed to support the weight of the vehicle while maintaining proper alignment of the wheels, which is vital for handling and stability. Struts also incorporate shock-absorbing capabilities, helping to control the impact from road irregularities and promoting a smoother ride. This dual function is essential for both the vehicle's structural integrity and passenger comfort, making struts a fundamental component in the dynamic performance of the vehicle.

The other choices do not reflect the primary function of struts. Improving aerodynamic drag relates to the vehicle's body design and components such as spoilers, while enhancing engine efficiency pertains to the powertrain and fuel systems. Lastly, controlling electrical systems is not relevant to struts, as they are mechanical components focused on suspension rather than electrical functionality.