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: Gynaecology & Obstetrics
CA 125 is elevated in all except : 
Select and explain. 
A. Tuberculosis, B. Endometriosis, C. Ovarian tumor, D. Polycystic ovarian disease
D: Polycystic ovarian disease
Answer: D: Polycystic ovarian disease 
Explanation: CA-125

This is a non-specific tumor marker
CA-125 is a glycoprotein which is normally not produced by ovarian epithelium but may be produced by both malignant and benign epithelial ovarian tumors.
Cut off level of CA-125 is < 35 U/mL.