Why Did Mendel Continue Some of His Experiments to the F2

Why did Mendel continue some of his experiments to the F2 or F3 generation?

A) to obtain a larger number of offspring on which to base statistics
B) to observe whether or not a recessive trait would reappear
C) to observe whether or not the dominant trait would reappear
D) to distinguish which alleles were segregating
E) to be able to describe the frequency of recombination