Please answer the following question: Passive immunity lasts only as long as the antibodies survive in body fluids, and factors in Body Fluid Health Potassium and sodium are crucial to the body's fluid balance. Given these facts, passive immunity lasts when the antibodies survive in something containing what among the following options: - fever - Leptospirosis - resistance - Chlorophyll - potassium - disease - bacteria - parasites
A:
potassium