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 not included under Garrod's tetrad 
Select and explain. 
A. Albinism, B. Pentosuria, C. Phenylketonuria, D. Cystinuria
C: Phenylketonuria
Answer: C: Phenylketonuria 
Explanation: Garrod's tetrad includes Albinism, Pentosuria, Alkaptonuria, Cystinuria.