Why Can the Lead-Acid Batteries Used in Cars Generate Electricity

Why can the lead-acid batteries used in cars generate electricity for several years before running down?

A) A lead-acid battery is so large that it holds large quantities of the chemicals whose electrochemical interaction creates the electricity.
B) The mechanical motion of the engine drives an alternator that generates electricity to recharge the battery.
C) These batteries are used only to generate the electricity that makes the first spark plug "spark." Therefore,they are hardly used at all when a car is started,and never when it is driven.
D) The electrons they generate,not the chemical components,provide almost all of the electricity.