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: Pathology
In pleomorphic adenoma mutation occurs in: 
Select and explain. 
A. PLAG1 gene., B. PLAM1 gene, C. PLAG2 gene, D. All of the above.
A: PLAG1 gene.
Answer: A: PLAG1 gene. 
Explanation: None