The correct option is D Sporozoites
The life cycle of Plasmodium that infect humans follows three stages:
(i) infection of a human with sporozoites
(ii) asexual reproduction and
(iii) sexual reproduction.
The two first take place exclusively into the human body, while the third one starts in the human body and is completed into the mosquito organism. The human infection begins
when an infected female Anopheles mosquito bites a person and injects the infected stage sporozoites into the blood circulation.