From fossil evidence, you know two species shared a common ancestor approximately 50 million years ago. In comparing a known neutral sequence between rats and mouse, you found 92 base differences in 1000bp. From this information, which of the following values is closest to what you would predict the mutation rate to be? a. 1 x 10-9
b. 4 x 10-9
c. 2 x 10-9
d. 5 x 10-9
e. 5 x 10-8
f. 8 x 10-9