............. are specialized parenchyma cells.
A. Sclereides are excessively thick walled short sclerenchyma cells provides stiffness and protection in various parts of the plant body.
B. Fibres are long, narrow, spindle shaped sclerenchyma cells having tapering ends, show elastic property.
C. Transfer cells are the specialized parenchyma cells having a large number of infoldings or protuberances formed from plasma membrane. It takes part in short distance transport of solutes, and nectar.
D. Tracheids are the dead cells with lignified walls and wide lumen present in the xylem, functions as a channels for transport of water and minerals.
So, the correct answer is 'Transfer cells'.