Geitonogamy involves:

1. fertilization of a flower by the pollen from another flower of the same plant.
2. fertilization of a flower by the pollen from the same flower.
3. fertilization of a flower by the pollen from a flower of another plant in the same population.
4. fertilization of a flower by the pollen from a flower of another plant belonging to a distant population.

Geitonogamy is the transfer of pollen grains in different flowers of same plant.