Nitabuch'slayer is absent is

Ans is 'a' i.e., Placenta accreteNitabuchs layerDuring formation of placenta, there is an area of fibrinoid degeneration where trophoblast cells (covered with syncytium) meet the decidua. This zone is known as Nitabuch's layer. This layer limits fuher invasion of the decidua by the trophoblast. Note: This membrane is absent in placenta accreta.