A cellular phone service company charges 20 cents for each minute or part of a minute of airtime. If the total charge y is a function of the number of minutes x that Cora uses her phone, what is the range of this function?
A. {0, 1, 2, 3, 4, . . .} C. {0, 20, 40, 60, . . .}
B. 0 0