In corn kernels, the traits for purple color (P) and round kernels (S) are dominant. The traits for yellow color (p) and shrunken kernels (s) are recessive. A cross is made between two plants that are each heterozygous for both traits. What is the probability of producing a yellow, shrunken kernel in the offspring?
a) 1/16
b) 1/8
c) 1/4
d) 1/2