Specialization in production a. All of the responses are correct. b. requires money. c. stimulates exchange. d. raises productivity.

1. When producers or workers specialize in a particular good or service, they focus on what they do best, which generally \( \text{raises productivity} \) because the division of labor leads to improved efficiency. 2. Specialization encourages the production of surplus goods, which then creates a need for \(\text{stimulated exchange}\) because individuals or groups trade these surplus goods to acquire other products they need. 3. For effective exchange, a common medium such as money is often used, because it simplifies transactions. Therefore, specialization indeed \(\text{requires money}\) to facilitate trade. Since all individual statements are correct, the overall answer is: \( \boxed{\text{All of the responses are correct.}} \)