Concept:An entrepreneur is someone who takes financial risks to start and manage a business.Explanation:A sole proprietor owns and runs the business alone.He sources for funds to establish the business and takes all the risks.He makes key decisions and enjoys the profits or bears the losses.Board members, debenture holders, and bank managers do not directly bear this entrepreneurial risk.Therefore, the sole proprietor is the best example of an entrepreneur among the options given.Answer:D. sole proprietor