Which part of a vehicle's interior extends from the windshield to the interior passenger area under the roof?

The headliner is the correct answer because it is the fabric or material that covers the interior roof section of a vehicle, extending from the windshield back to the rear seat area. It plays an important role in a vehicle’s insulation, aesthetics, and acoustics, helping to reduce noise and improve the overall appearance of the interior space.

The sunroof is an opening in the roof that may be covered by glass or a sliding panel, allowing light and air into the vehicle, but does not cover the entire area under the roof. The dashboard refers to the panel facing the driver and front passenger, housing controls and instruments, and is positioned much lower than the headliner. The headrest is designed to support the head of passengers in a seat, primarily for comfort and safety, and is not related to the interior roof area. Thus, the specific definition and role of the headliner clearly establish it as the distinctive element in the vehicle's interior.