The correct option is D All of the above
Self pollination is a form of pollination that can occur when a flower has both stamen and a carpel in which the sultivar or species is self fertile and the stamens and the sticky stigma of the carpel contact each other in order to accomplish pollination. It is prevented by: dichogamy, self-sterility and hekrogamy. Dichogamy - having pistils and stamens that mature at different times, thus promoting cross-pollination rather than self pollination. Herkogamy - common strategy employed by angiosperms to reduce sexual interference between male (anthers) and female (stigma) function.