Final answer:
Rachel overcame functional fixedness by using a charger cord as a makeshift tape measure to determine her calf size for boots.
Step-by-step explanation:
When Rachel used a charger cord as an improvised measuring tool to check her calf size for boots, she demonstrated overcoming functional fixedness. Functional fixedness is a cognitive bias that limits a person to using an object only in the way it is traditionally used. However, Rachel showed creativity by repurposing an everyday object to solve her problem, illustrating the process of overcoming functional fixedness, which is the correct answer to her question, option (b).