Xenogamy : Only types of pollination which brings genetically different types of pollen grains to the stigma. 

Option B is correct becose i will eliminate one by one option geitonamy is ecologycally different that men's it contains cross pollination.. genetically similar that means it contains self pollination, chamogamy (always occurs in cletrogamas flowers )it only contains self pollination.. atogamy is also called self pollination, Xenogamy is genitacally and Ecologically cross pollination..

Xenogamy is the type of pollination that brings genetically different types of pollen grains to the stigma of a plant. Let's understand this in more detail:

What is pollination?
Pollination is the transfer of pollen from the male reproductive organ (anther) to the female reproductive organ (stigma) of a flower. It is a crucial step in the sexual reproduction of plants.

What is xenogamy?
Xenogamy is a type of pollination in which pollen grains from a different plant of the same species are transferred to the stigma of a flower. This results in the fusion of genetically different male and female gametes, leading to the production of genetically diverse offspring.

How is xenogamy different from other types of pollination?
1. Autogamy - It is the self-pollination of a flower, i.e., the transfer of pollen from the anther to the stigma of the same flower or another flower on the same plant. This results in the fusion of genetically identical male and female gametes, leading to the production of genetically identical offspring.
2. Geitonogamy - It is the transfer of pollen from the anther of one flower to the stigma of another flower on the same plant. This results in the fusion of genetically similar male and female gametes, leading to the production of offspring that are not genetically diverse.
3. Chasmogamy - It is the type of pollination in which the flowers are open and exposed, allowing for easy transfer of pollen. This is in contrast to cleistogamy, where the flowers are closed, and pollination occurs within the closed bud.

Why is xenogamy important?
Xenogamy is important for the survival of plant species as it results in the production of genetically diverse offspring. This genetic diversity allows plants to adapt to changing environmental conditions and increases their chances of survival. Additionally, xenogamy also helps in the exchange of genes between different populations of the same species, resulting in increased genetic diversity at a larger scale.

In conclusion, xenogamy is the type of pollination that brings genetically different types of pollen grains to the stigma of a plant, resulting in the production of genetically diverse offspring.