Which of These Methods Does Not Help Promote Outcrossing in Plants

Which of these methods does not help promote outcrossing in plants?

A) Staminate flowers and pistillate flowers reach maturity at different times.
B) Genetic self-incompatibility,even when staminate flowers and pistillate flowers reach maturity at the same time.
C) Flowers in which stamens and stigmas do not come in contact with each other.
D) Staminate and pistillate flowers mature at the same time,and are able to undergo self-pollination.
E) Physical separation of the staminate and pistillate flowers.