d all of these
Fertilization is where the egg cell of the females meet the sperm cell of the males, Further it is even a step by step process, stated in the provided options.
Considering that the female and male sex cells are present
1. Sperm must swim into an oviduct.
2. b An oocyte must be present in the oviduct.
3. c The nucleus of a sperm must fuse with an oocyte nucleus.
