Read the following statements carefully.

A: Formation of bisexual and homogamous flowers.

B: Formation of cleistogamous flowers.

The above contrivances favors -

The presence of bisexual flowers is the most basic requirement in order to achieve autogamy or self-pollination.

In homogamous flowers, anthers and the stigma of a flower are being matured at the same time and therefore promote self-pollination (autogamy).

Cleistogamous flowers do not open at all. In such flowers, the anthers and stigma lie close to each other. When anthers dehisce in the flower buds, pollen grains come in contact with the stigma to effect pollination. Thus, cleistogamous flowers are invariably autogamous as there is no chance of cross-pollen landing on the stigma.