What are the possible types of pollination in chasmogamous flowers? Give reasons.

(N/A) Chasmogamous flowers are flowers which are open,exposing their anthers and stigmas. Due to this exposure,they can undergo both self-pollination and cross-pollination.
$(A)$ Self-pollination (Autogamy): In this type,pollination occurs within the same flower. Pollen grains are transferred from the anther to the stigma of the same flower. This is possible in chasmogamous flowers if the anthers and stigma mature at the same time (homogamy) or are positioned close to each other.
$(B)$ Cross-pollination (Allogamy): This involves the transfer of pollen grains from the anther of one flower to the stigma of another flower. It is of two types:
$(i)$ Geitonogamy: Transfer of pollen grains from the anther to the stigma of another flower on the same plant. Functionally,it is cross-pollination involving a pollinating agent,but genetically,it is similar to autogamy because the pollen grains come from the same plant.
$(ii)$ Xenogamy: Transfer of pollen grains from the anther of one flower to the stigma of a flower on a different plant of the same species. This is the only type of pollination that brings genetically different types of pollen grains to the stigma.