For Mendel to have postulated the law of independent assortment which of the following reasons had to be valid?

A) All the traits that Mendel examined involved genes that did not display genetic linkage.
B) Several of the phenotypes that Mendel examined involved color.
C) Mendel observed chromosomal segregation in pea-plant cells.
D) Mendel carried out his experiments on plants and not on fungi.
E) None of the above