Final answer:
A turbo boost in a CPU refers to a feature that automatically overclocks the CPU for improved performance.
Step-by-step explanation:
A turbo boost, in the context of a CPU (Central Processing Unit), refers to a feature that automatically overclocks the CPU for improved performance.
Option c) 'Automatically overclock for improved performance' is the correct answer to the question. When a CPU is under high demand, the turbo boost feature increases its clock speed temporarily to handle the workload more efficiently.