Go through the following statements:
- Flowers are bisexual and homogamous maturing anther and stigma of a flower at the same time.
- Mechanical devices bringing anthers and stigma close together in a bisexual chasmogamous flower.
- Cleistogamy (bisexual flowers remain closed)
- Anther and stigma of an intersexual flower mature in bud condition.
The above contrivances favour:
(a) Allogamy (b) Autogamy (c) Xenogamy (d) Cross pollination