6. Food Express is running a special promotion in which customers can win a free gallon of milk with their food purchase if there is a star on their receipt. So far, 147 of the first 156 customers have not received a star on their receipts. What is experimental probability of winning a free gallon of milk?

A. 11/156
B. 49/52
C. 2/39
D. 3/52*****?