Following the sequence of Mendel’s heritability study, which of the following is true? A Mendel began by breeding two of the same

Following the sequence of Mendel’s heritability study, which of the following is true?

A
Mendel began by breeding two of the same true-breeding parents.
B
Mendel began by breeding two different types of true-breeding parents.
C
The offspring of the P generation were known as the first filial generation.
D
Both B and C.