This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Kidneys and Body Fluids, Subject name: Physiology
A substance is present in concentration of 2mg% in the afferent arteriole and zero mg% in the efferent. True about the substance is 
Select and explain. 
A. It is freely filtered in glomerulus, B. Secreted in cortical nephron, C. Absorbed in PCT, D. Impermeable in loop of Henle
A: It is freely filtered in glomerulus
Answer: A: It is freely filtered in glomerulus 
Explanation: Ans. (a) It is freely filtered in glomerulus(Ref: Ganong, 25th ed/p.673)Concentration of 0 mg% means the substance is freely filtered into the bowman's space