In Mendel's pea plant experiments, in order for him to have observed a 3:1 phenotypic ratio in the F₂ generation, which of the following must be true?

A) The two alleles of a pair separate in gamete formation.
B) The pairs of alleles must be either homozygous dominant or homozygous recessive.
C) Both alleles of a pair must go into each gamete together.
D) Both of the F₁ parents must be breed true.