4. Flavor Enterprises has been approached about providing a new service to its clients. The company will bill clients $140 per hour; the related hourly variable and fixed operating costs will be $75 and $18, respectively. If all employees are currently working at full capacity on other client matters, the per-hour opportunity cost of being unable to provide this new service is: A. $0. B. $47. C. $65. D. $93. E. $140