Final answer:
The answer to the question is A. Vehicle door locks should indeed be oiled periodically to maintain smooth operation, using a lubricant like dry graphite or one recommended for modern lock mechanisms.
Step-by-step explanation:
It is recommended to oil vehicle door locks periodically to ensure their smooth operation. This maintenance helps to prevent the locks from sticking and reduces wear and tear. Traditionally, a dry graphite lubricant is used because it does not attract dirt and debris, which can gum up the mechanism.
However, modern cars with more complex lock mechanisms may require a different type of lubricant, so it's important to refer to the vehicle's owner's manual or consult with a professional mechanic for the appropriate product.