<prompt> Lambda sign or twin peak sign is seen inDiamniotic MonochorionicDichorionic DiamnioticMonochorionic monoamnioticNone of the above  <response>: The Lambda or Twin peak sign at 10-14 weeks of gestation demonstrate the high reliability of ultrasound examination in determining chorionicity in twin pregnancies. The T sign is really the absence of a twin-peak signor lambda l sign and is used in ultrasound assessment of multifetal pregnancy. It refers tothe lack of chorion extending between the layers of the intewin membrane, denoting a monochorionic diamniotic pregnancy. 