Answer- C- Plasmodium falciparum
Given clinical presentation suggestive of malaria.
Double rings in erythrocytes & banana-shaped gametocytes on a peripheral blood smear – Typical P. falciparum infection.
The early ring form in the erythrocyte is very delicate and tiny, measuring only one-sixth of the red cell diameter. Rings are often seen attached along the margin of the red cell, the so-called form applique or accole.
Binucleate rings (double chromatin) are common resembling stereo headphones in appearance. Several rings may be seen within a single erythrocyte.
Decreased skin turgor is a key marker of severe intra-cellular dehydration, and so more typical of severe gastroenteritis than severe malaria.