Michael Porter's five forces model includes which one of the following combinations?
1. A Threat of new potential entrants
2. Threat of substitute product/service
3. Bargaining power of suppliers
4. Bargaining power of buyers
5. Rivalry among current competitors
6. Rivalry among prospective competitors

A. 1, 3, 4, 5, 6

B. 1, 2, 4, 5, 6

C. 1, 2, 3, 5, 6

D. 1, 2, 3, 4, 5

Answer: Option D