This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
Twin Peak sign is characteristic of 
Select and explain. 
A. Dichorionic Diamniotic, B. Monochorionic Diamniotic, C. Monochorionic Monoamniotic, D. Conjoined twins
A: Dichorionic Diamniotic
Answer: A: Dichorionic Diamniotic 
Explanation: Determination of ZygositySonographic Determination:ChorionicityDividing inter-twin membrane thicknessSignDichorionicity> 2mmTwin peak sign or Lambda signMonochorionicity< 2mmT signReference: William's Obstetrics; 25th edition; Chapter 45; Multifetal pregnancy