since i dont have the genotype for the wrinkled seeds, i'm assuming it is homozygous recessive ie (rr)
from the question the genotype for the round seed is heterozygous(different) hence the Rr
the F1 generation means direct children of the parents, therefore crossing Rr and rr will give the genotypes in (c)
F2 generation is the children of the children (grandchildren), therefore
crossing two round plants (Rr and Rr) will produce the offspring in (d)
Please let me know if you need any clarification. I'm always happy to answer your questions.