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
Which of the following is a mitochondrial enzyme of Urea Cycle 
Select and explain. 
A. Arginase, B. Carbamoyl Phosphate synthetase I, C. Arginosuccinate lyase, D. Arginosuccinate synthetase.
B: Carbamoyl Phosphate synthetase I
Answer: B: Carbamoyl Phosphate synthetase I 
Explanation: CPS - I is a mitochondrial enzyme and catalyses rate limiting step of Urea Cycle.
All the Cytoplasmic enzymes of urea cycle start with letter "A".