Final answer:
George's inability to solve the problem and use the blanket is due to a) functional fixedness, which is a mental set that limits one's ability to perceive alternative uses for objects.
Step-by-step explanation:
George's inability to solve the problem and use the blanket is due to a) functional fixedness, which is a type of mental set where one cannot perceive an object being used for something other than what it was designed for.
In this case, George only associates the blanket with sleep and does not consider using it as a makeshift umbrella. Functional fixedness can limit problem-solving abilities by restricting one's thinking to predetermined uses of objects.