Right choice is (d) Humans
Easiest explanation: Syngamy is the process of fertilization that produces a diploid cell on the fusion of two haploid cells. It is also often called internal fertilization since the process takes place on the inside. However, there are few species of organisms where syngamy occurs outside their bodies, in an external medium. Example, algae, fishes, amphibians, etc. This is also called as external fertilization.