Final answer:
The correct parental genotypes to yield a 9:3:3:1 phenotypic ratio are SsYy x SsYy, indicating that both parents are heterozygous for both traits. This ratio matches Mendel's law of independent assortment, reflecting the diverse combination of traits in the offspring. Therefore, the correct option is c.
Step-by-step explanation:
The 9:3:3:1 phenotypic ratio mentioned in the student's question indicates a dihybrid cross involving two pairs of contrasting traits. This ratio is typical for offspring inheritance patterns when both parents are heterozygous for both traits, meaning each parent carries both dominant and recessive alleles for both traits under consideration. The correct parental genotypes that would most likely result in a 9:3:3:1 ratio are SsYy x SsYy. Each parent has one allele for smooth coat (S, dominant) and rough coat (s, recessive), plus one allele for yellow seeds (Y, dominant) and green seeds (y, recessive).
Both traits—seed color and texture—are assumed to be inherited independently according to Mendel's law of independent assortment. When these two parents are crossed, their offspring have a range of combinations of these traits, leading to the 9:3:3:1 ratio: 9/16 will be smooth-coated and yellow-seeded (dominant for both traits), 3/16 will be smooth-coated and green-seeded, 3/16 will be rough-coated and yellow-seeded, and 1/16 will be rough-coated and green-seeded (recessive for both traits).