Motile zygote of Plasmodium occurs in:
Gut of female Anolpheles
Salivary glands of Anopheles
Human RBCs
Human liver
The Plasmodium genus causes malaria, an infectious disease spread by mosquitoes that affects both humans and other animals. Gametocytes are absorbed with the blood and mature in the mosquito gut in the female Anopheles mosquito. A fertilized, mobile zygote called an ookinete is created when the male and female gametocytes combine. In order to infect a new vertebrate host, ookinetes mature into fresh sporozoites that move to the insect's salivary glands.
Therefore, "Gut of female Anopheles" is the right response.