This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Biochemistry
Plasma levels of which of the following are likely to be lower than normal in a case of severe liver disease? 
Select and explain. 
A. NH3, B. NH4+, C. Urea, D. Alanine
C: Urea
Answer: C: Urea 
Explanation: .