Which adjustment can significantly enhance a race car's acceleration?

Adjusting the rear wing angle can significantly enhance a race car's acceleration because it directly impacts the car's aerodynamic properties. The rear wing provides downforce, which increases tire grip and stability, allowing the car to maintain higher speeds through corners and accelerates more effectively out of turns. By optimizing the wing angle, the balance between downforce and drag can be fine-tuned, enhancing overall performance.

In contrast, changing the color of the car does not affect its mechanical or aerodynamic capabilities, so it wouldn't have any impact on acceleration. Modifying the driver’s race attire is also unrelated to the car's performance since the driver’s clothing does not influence the vehicle dynamics. Reducing tire pressure significantly might have negative effects on handling and could lead to increased rolling resistance and potential tire damage, making it counterproductive in terms of acceleration. Thus, adjusting the rear wing angle stands out as the only option directly related to improving the car's acceleration.