Let's analyze the question to understand what is being asked:
The question is looking for a term that describes the "attractive idea that an entrepreneur invests in." This points toward a concept in innovation and entrepreneurship.
Let's examine each option to find the most appropriate term:
Therefore, given the context of the question relating to entrepreneurship, the correct choice is the term Opportunity. It signifies a specific, actionable idea that holds the potential for successful investment and growth, aligning well with what entrepreneurs seek.