The correct option is B Fertilisation, zygote
Male and female gametes are the reproductive cells of an organism. Fertilisation is the fusion of male and female gametes of an organism. A zygote is a single cell formed during fertilization. The embryo is an early stage development of the zygote. Embryogenesis is the development of an embryo. Implantation is an event of the embryo attaching to the uterus wall.