The correct option is B Vivax and falciparum
The genus of the given options are as follows:
Homo sapiens (man)
Pavo cristatus (Indian peafowl)
Entamoeba histolytica (parasitic protozoan)
Columba livia (rock pigeon)
Gavialis gangeticus (gharial)
Vivax and falciparum, both belong to the Plasmodium genus, which is the genus of parasitic protozoa.
So, the correct answer is option B.