A local vendor at the county fair sells snow cones for $.50 each. When 250 snow cones are sold, each snow cone is estimated to have $.10 in variable costs and $.15 in fixed costs. A local school group plans on attending the fair next week and wishes to purchase 50 snow cones for $.25 each. The vendor can sell as many as 400 snow cones per day. What is the minimum price the vendor should charge for the snow cones?
a. $.75
b. $.25
c. $.10
d. $.50