Hich is an example of a proportional relationship?
A.The yogurt shop charges .30 per pound.
B.The yogurt shop charges .30 per pound plus $1.00 for the cup.
C.John ran 2 miles in 15 minutes then ran 3 miles in 20 minutes.
D.The car travelled 40 mph for half an hour and then travelled 60 mph for 2 hours