​coinstar total fixed cost of operating one​ self-serve kiosk is the cost of​ ______.    ​coinstar variable cost of providing coffee at a​ self-serve kiosk is the cost of​ ______.

a. the personnel who handle refills of coffee beans and​ milk; the coffee beans and milk

b. the​ machine, coffee​ beans, and​ milk; the workers who provide maintenance services

c. the coffee beans and​ milk; the machine and the workers who provide maintenance services

d. the​ machine; the coffee​ beans, milk, and workers who provide maintenance services