Which of the following is part of plasmodesmata-(1) plasma membrane(2) desmotubule(3) cytoplasmic strands(4) all of these

Ans is all of these.
Fine cytoplasmic strands that connect theprotoplastsof adjacent plant cells by passing through their cell walls. Plasmodesmata are cylindrical in shape and are lined by the plasma membrane of the two adjacent cells. The endoplasmic reticula of the two adjacent cells are connected by a narrower structure, thedesmotubule, which runs through the centre of a plasmodesma