Final answer:
The fuse is the correct answer; it limits the amount of current through the armature in a 12V system to protect it from damage due to overcurrent conditions.
Step-by-step explanation:
The purpose of the fuse in the 12V system is to protect the armature windings by limiting the amount of current through the armature. A fuse is a safety device designed to protect electrical circuits from excessive current that can cause damage or even a fire. When current flowing through the circuit exceeds a certain level, the wire within the fuse heats up and melts, breaking the circuit and preventing further damage. While other components like resistors, capacitors, and diodes have different functions within a circuit, fuses and circuit breakers are specifically meant to act as safeguards against current overload by acting as automatic switches that open when sustained current exceeds desired limits.