The correct options are
A It has short life cycle
B It undergoes self-pollination
D It shows contrasting heritable characters
Mendel selected the pea plant for his experiments because this plant has a short life cycle, and shows distinct contrasting characters. It possesses bisexual flowers that undergo self-pollination, while they could also be conveniently cross-fertilised. Also, he could obtain large number of progeny which made his experimental results more valid.