A company was founded by two brothers in a certain city to provide in-home computer and electronic installation services as well as tech support to solve hardware, software, or computer peripheral crises. The company became highly successful with branches throughout the region and was purchased by a particular retail chain but continued to operate under its original name. A shipment of 28 processors was sent to the company. Twenty-one of them were defective. One of the company's technicians selected 5 of the processors to put in his parts inventory, and went on three service calls. Complete parts a through c below. a. Determine the probability that only 1 of the 5 processors is defective. The probability is (Round to five decimal places as needed.)