<prompt> Most common type of monozygotic twin pregnancy at 4th-8th day of cell divisionMonochorionic Monoamniotic twins with Siamese presentationMonochorionic MonoamnioticMO-MO twinsMonochorionic Diamniotic twinsMO-DIDichorionic Diamniotic twins DI-DI  <response>: In monozygotic twins, chorionicity depends upon time of cell division. Time of cell division Chorionicity of placenta First 72 hours post feilizationmorula stage DCDA 4-8th dayblastocyst stage MCDAMC type of monozygotic twins 8-12th day MCMA 12th day ConjoinedSiamese twins, type of MCMAfusion of embryonic disc occurs 