Irving's Rib Shack is a regional chain of barbecue restaurants. They have a long-standing policy that the recipe for their signature barbecue sauce is not to be made public. What type of intellectual property protection keeps the recipe secret?

The correct answer is trade secret

Explanation:

Trade secret can be considered as any secret or confidential information regarding business that provides a company with a competitive advantage over other company's in the market. Trade secret can be anything like commercial secrets, advertising strategies, recipe formula or manufacturing secrets etc. So therefore by reading the question it is quite clear that the intellectual property protection that keeps the recipe a secret is trade secret.