The Garden Pea Was a Good Model for Mendel's Genetics

The garden pea was a good model for Mendel's genetics experiments. Which of the following is not true regarding this model organism?

A) The plants were easy to grow.
B) Pea plants can either cross-pollinate or self-pollinate.
C) There was only one variety of pea available to Mendel.
D) All inheritance patterns were simple.
E) Most of the traits studied had no intermediate stage.