Which of the Following Reasons Was Essential for Mendel to Disprove

Which of the following reasons was essential for Mendel to disprove the theory of blended inheritance?

A) The traits that Mendel examined all involved genes that did not display linkage.
B) The traits that Mendel examined all involved the reproductive structures of the pea plant.
C) Mendel pioneered techniques permitting the fusion of male and female gametes from the same plant to produce a zygote.
D) The traits that Mendel examined involved an allele that was dominant and an allele that was recessive.