In Mendel's Pea Plants, Yellow Seeds Are Dominant to Green

In Mendel's pea plants, yellow seeds are dominant to green seeds. Purple flowers are dominant to white flowers. Use Y and y for the seed color alleles, and P and p for the flower color alleles. Flower color and seed color assort independently. If a plant that is heterozygous for both flower color and seed color genes is self-fertilized, what proportion of the offspring will have one of the dominant phenotypes, either the seed color or flower color, but not both?

A) 6/64
B) 6/32
C) 6/16
D) 9/32
E) 9/16