Which of the following types of pollination lead to genetic variation?

The correct option is B. Xenogamy

In both autogamy and geitonogamy, male and female gametes are derived from the same parent and the progeny obtained almost resemble the parent plant. This means the genetic character of the male and female flowers is the same in both autogamy and geitonogamy as they take place in the same plant.

Cross-pollination or xenogamy enables the fusion of two genetically distinct plant characters, belonging to the same species. Therefore, it introduces genetic recombination and variations in plants due to the fusion of gametes that are genetically distinct.