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: Unknown
Regarding monozygotic twins, which of the following is not true? 
Select and explain. 
A. USG is more useful in the first half of pregnancy, B. Sex discordance can occur rarely, C. Always monochoriomc, D. More common following ovulation induction
C: Always monochoriomc
Answer: C: Always monochoriomc 
Explanation: Ans: C (Always monochorionic) Ref: DC Du f fa's Textbook of Obstetrics, 7th edn, Pg 201Explanation:Monozygotic twins are always identical in sex.Monozygotic twins can be:Diamniotic dichorionicDiamniotic monochorionicMonoamniotic monochorionicConjoint twinsMost common cause of multiple pregnanciesovulation inductionUltrasound in the first half of pregnancy is best to check for amnionitis and chorionicity.