The correct option is B Hypnozoite
In Plasmodium vivax and Plasmodium ovale, some of the sporozoites do not immediately undergo asexual replication, but enter a dormant phase, known as hypnozoite. This hypnozoite can reactivate and undergo schizogony at a later time resulting in a relapse. Relapse refers to the reactivation of the infection via hypnozoites. So, the correct answer is option C.