Please answer the following question: You are presented with the question "Passive immunity lasts when the antibodies survive in something containing what?" and the following answer choices: - fever - Leptospirosis - resistance - Chlorophyll - potassium - disease - bacteria - parasites Now knowing that 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, choose the best answer.
A:
potassium