The correct answer is b) sexual reproduction.
In sexual reproduction, genetic material from two parents combines to create offspring with genetic variation. This process involves the fusion of gametes (sperm and egg cells) from each parent, leading to the formation of a zygote, which then develops into a new organism. In contrast, asexual reproduction involves only one parent and produces genetically identical offspring, while processes like mitosis and meiosis are types of cell division related to growth and reproduction but do not necessarily involve two parents combining their genes.