Answer: The correct answer is 50%
Explanation-
Allele for yellow seed is dominant to the allele for green seeds.
Let 'Y' represents the allele of yellow seeds and y represents the allele for green seeds.
According to the question, genotypes of the parent plants are-
Hetrozygous Yellow seeds- Yy and Homozygous Green seeds- yy.
Percent of first generation with green seeds =

= 50 %