A pea plant with green pods is crossed with a pea plant with yellow pods. The F1 generation was all the same color. If 75% of the F2 generation have green pods and 25% have yellow pods, what conclusion can we make?

a. Both parent plants were true breeding.
b. The color of the F1 generation is needed to make a conclusion.
c. Yellow pods are the dominant form of the trait for pod color.
d. Neither parent plant was true breeding.