To help Dax determine if starting a business with his friend meets his needs, he should focus on questions that directly relate to control, collaboration, and his long-term goals for the business. Among the provided options, the most relevant question would be:
A. How much control of the business do you want?
This question addresses Dax's preference for being in charge and would help him evaluate how a partnership with his friend might affect his level of control over business decisions. It opens up discussions on decision-making authority, responsibilities, and how their roles would be structured within the company.
The other options (B, C, and D) are important considerations for starting a business but are not as directly tied to the fundamental partnership decision he is facing.