Final answer:
A scored drum surface is most commonly caused by corrosion, which leads to rusting and pitting, damaging the surface of the drum.
Step-by-step explanation:
A scored drum surface in the context of vehicle maintenance and repair is usually indicative of surface damage that may occur for various reasons. However, the correct answer to the question of what could cause a scored drum surface is b) Corrosion. This type of damage is characterized by roughened or grooved patches on the drum surface, which is part of the braking system on many vehicles. While overheating, improper lubrication, and metal fatigue are plausible answers, corrosion is the primary culprit that leads to scoring as it promotes rust and pitting on the metal surface, compromising its smoothness and functioning.