Please help,

Rob draws a marble out of a bag. It is either red or green. He records the color and then puts the marble back in the bag.
He repeats this process 50 times to get the following results:

Red: 13

Green: 37

Because Rob knows that there are 4 marbles in the bag, he knows that the probability of choosing a red marble must be either 1/4, 2/4, 3/4, or 4/4. Based on his data, which of these models is most probable?

A. 1/4
B. 2/4
C. 3/4
D. 4/4