Final answer:
The NEC required category of motor protection is Overload, where protection devices like fuses and circuit breakers prevent excessive current from causing overheating and related hazards.
Step-by-step explanation:
Among the NEC required categories of motor protection, the option A) Overload is correct. Overload protection is essential to prevent motor damage due to excessive current that can cause overheating. Electrical wires and appliances are rated for a maximum current they can safely handle. This condition, where the current exceeds this rated maximum current causing the wires to overheat, refers to the term 'overloaded'. To avoid such scenarios, fuses and circuit breakers are utilized to limit excessive currents that may lead to thermal hazards, equipment damage, and even electric shock.