Malaria’s caused by Plasmodium parasites—mostly P. falciparum and P. vivax—which attack your red blood cells and settle in the liver. As these parasites multiply, your spleen really takes a hit. It’s busy trying to filter out all those infected red blood cells and ramp up your immune response, so it often gets enlarged, a condition called splenomegaly. Sure, if things get bad, other organs like the kidneys or brain can suffer too, but the spleen stands out as the main organ that’s visibly affected in most cases. So, the correct answer is (B) Spleen.