This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gynaecological oncology, Subject name: Gynaecology & Obstetrics
Ovarian tumour staging if one ovary involved without surface involvement or rupture 
Select and explain. 
A. Stage 1A, B. Stage 1B, C. Stage 1C1, D. Stage 1C2
A: Stage 1A
Answer: A: Stage 1A 
Explanation: STAGE 1A: Ovarian cancer limited to one ovary without malignant ascites or positive peritoneal washings, surface involvement or rupture