In Pisum sativum, a pea plant, the allele for yellow seed color (Y) is dominant over the allele for green seed color (y). Two plants were crossed; three-fourths of the offspring plants had yellow seeds, and one-fourth of the offspring plants had green seeds. Based on these results, what were the genotypes of the parent plants? A   Yy, yy B   Yy, Yy C   YY, yy D   YY, Yy