Charlie is at an amusement park that has 18 different rides. Each ride costs $1.75. The function C(r) = 1.75r represents the total amount of money that Charlie will spend if he goes on r rides, but he never goes on the same one more than once. What domain and range are reasonable for the function?
A.
D : 0 ≤ r ≤ 31.5
R : 0 ≤ C(r) ≤ 18
B.
D : 0 ≤ r ≤ 18
R : 18 ≤ C(r) ≤ 31.5
C.
D : 1 ≤ r ≤ 18
R : 1.75 ≤ C(r) ≤ 31.5
D.
D : 0 ≤ r ≤ 18
R : 0 ≤ C(r) ≤ 31.5