Sue bought a bunch of snacks that each cost $2.50. Let y represent the total cost and x represent the number of snacks she bought. Pick which equation represents the proportional relationship between the total cost and the number of snacks she bought.
A.) 2.50(y) = x
B.)2.50 + y =x
C.) 2.50(x) = y
D.) 2.50 + x = y