This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Female Genital Tract, Subject name: Pathology
Best fixative for Pap smear: 
Select and explain. 
A. 95% ethanol + 5% ether, B. 10% formaldehyde, C. 80% isopropyl alcohol, D. 90% ether + alcohol
A: 95% ethanol + 5% ether
Answer: A: 95% ethanol + 5% ether 
Explanation: ANS. AFixatives:* Pap smear: 95% ethanol + 5% ether* Light microscopy: 10% formaldehyde* Electric microscopy: 2% glutaraldehyde* For liquid-based cytology: Methanol* For bone marrow biopsy: Zenker's fluid* For bone marrow aspirate: Helly's fluid* Cell block: Bouin's fluid* Karyotyping fixatives: Carnoy's fixative (3:1 methanol to glacial acetic acid)* Gastrointestinal biopsies: Bouin's fluid.