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 fanconi anemia, there is a 
Select and explain. 
A. Deficiency of copper, B. Mutation of DNA repair gene, C. No increased risk of squamous cell carcinoma, D. Purely nutritional disorder etiology
B: Mutation of DNA repair gene
Answer: B: Mutation of DNA repair gene 
Explanation: None