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: Surgery
Of the following the most significant risk factor for developing breast cancer is- 
Select and explain. 
A. The presence of sclerosing adenosis, B. Nullipartiy, C. Atypical lobular hyperplasia, D. Atypical ductal hyperplasia
D: Atypical ductal hyperplasia
Answer: D: Atypical ductal hyperplasia 
Explanation: None