This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
Gain of function mutation in RAS gene is equal to loss of function mutation in 
Select and explain. 
A. Rb, B. Bcr-tyrosine kinase, C. Bcl-2, D. GAP protein
D: GAP protein
Answer: D: GAP protein 
Explanation: None