Which form of reproduction results in the highest degree of genetic variation among offspring?

The correct answer is:  sexual reproduction

Sources of genetic variation are different:

•Genetic mutations-random and rare events that occur within the genome and contribute to variations among individuals (or population). Mutations might be neutral, harmful or beneficial when they form new alleles favored by natural selection.

•Crossing over (genetic recombination)-event that occur during the meiosis (cell division that creates gametes)

•Random segregation during meiosis

•Random fertilization

•External source such as transposable genetic elements or retroviruses.