Assume there are 13 homes in the Quail Creek area and 4 of them have a security system. Three homes are selected at random: a. What is the probability all three of the selected homes have a security system? (Round your answer to 4 decimal places.) b. What is the probability none of the three selected homes has a security system? (Round your answer to 4 decimal places.) c. What is the probability at least one of the selected homes has a security system? (Round your answer to 4 decimal places.)