If the range of the function is f(x) = 5/x + 6.5 is {7, 6.83, 6.78, 6.75}, what is its domain?
a) {5, 10, 15, 20}
b) {10, 15, 18, 20}
c) {10, 15, 17, 20}
d) {10, 14, 16, 20}
e) {8, 15, 18, 22}