Final answer:
The most cited source of new business ideas is an in-depth understanding of an industry or profession, which allows for the identification of market needs and opportunities for innovation.
Step-by-step explanation:
The most cited source of new business ideas is often an in-depth understanding of an industry or profession. This knowledge provides insights into market gaps, customer needs, and potential innovations which can be turned into business ideas. However, brainstorming sessions can lead to a variety of ideas based on different perspectives and backgrounds. Hobbies can inspire business ideas when an individual recognizes a product or service that can be offered to like-minded enthusiasts. Copying someone else's idea may occur, but it's not typically recognized as a credible or ethical source of new ideas. Successful businesses rely on unique value propositions and innovation rather than simply copying existing concepts.