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
Breast conservation surgery is indicated in one of the following conditions -a) T1 breast tumorb) Multicentric tumorc) Extensive in situ cancerd) T4b breast tumor 
Select and explain. 
A. a, B. bc, C. ad, D. ac
D: ac
Answer: D: ac 
Explanation: None