This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Phenylbutyrate is used in the treatment of urea cycle disorders, because 
Select and explain. 
A. It activates deficient enzymes, B. It maintains urine output, C. It acidifies the urine, D. It scavenges nitrogen.
D: It scavenges nitrogen.
Answer: D: It scavenges nitrogen. 
Explanation: Phenylbutyrate and sodium benzoate act as ammonia(nitrogen) scavengers.