Mendel Wanted to Make Sure His Starting Plants Bred True,meaning

Mendel wanted to make sure his starting plants bred true,meaning the:

A) seeds would always sprout.
B) peas would always be green.
C) phenotypes of the offspring in each generation could not be predictable.
D) phenotypes of the offspring in each generation were always the same as the parent.
E) phenotypes of the offspring in each generation would sometimes look like the male parent and sometimes look like the female parent.