During Mendel's second set of experiments, he allowed the F1, offspring from the first experiments to self-pollinate. Which of the following best describes the results? O A. About 25% of the Fz offspring expressed a different version of the studied trait than the parents had. O B. All the F2 offspring expressed a different version of the studied trait than the parents had. O C. All the F2 offspring expressed the same version of the studied trait as the parents had. D. About 25% of the Fz offspring expressed the same version of the studied trait as the parents had.​