a business that owners buy into with a proven standard system of operation is called a(n)\nmanaged…

Brief Explanations:

A franchise is a business model where an owner buys into a proven standard system of operation. The franchisor provides the brand - name, products, and operational guidelines. Managed business is more about a third - party managing a business, chain is a group of similar businesses but not necessarily with a bought - in system, and independent business operates without such a pre - set system.

Answer:

B. franchise