7. A toll-free phone number is available from 9 a.m. to 9 p.m. for your customers to register complaints about a product purchased from your company. Past history indicates that an average of 0.6 calls are received per minute. What is the probability that during a 1-minute period three or more phone calls will be received?

a. 0.0231 b. 0.769 c. 0.651 d. 0.856