The aspect of the American economic system that is most beneficial in helping entrepreneurs like Bill Gates succeed is the free enterprise system (option B). The free enterprise system promotes competition, innovation, and entrepreneurship by allowing individuals to start businesses, make their own economic decisions, and benefit from their own efforts and successes. This system fosters an environment where entrepreneurs can take risks, create new products or services, and grow their businesses. Bill Gates, as a successful entrepreneur, was able to thrive within this system by founding Microsoft and leveraging the opportunities provided by the free enterprise system.