In pease, smooth seeds are dominant to wrinkled seeds. When a plant with smooth seeds was crossed with a plant

having wrinkled seeds, 50% of the offspring were smooth and 50% were wrinkled. What does this indicate about smooth-seed parent? A. it was zygous recessive B. it was zygous dominant C. it was probably "true-breeding" D. its genotype is unknown E. it was heterozygous