I believe the "I'm" is supposed to be "in" and if so then the correct nswer would be External Fertilization... because as the name suggests, external fertilization means fertilization takes place outside the body of the organism. In this process, mating partners release eggs and sperm outside their body, which then undergo fertilization.
External fertilization occurs in aquatic animals ( like fishes) as the presence of water gives sperm a medium to travel to the eggs and fertilize them.