Consider the following statements: (a) In exarch xylem, the protoxylem is situated towards the center of the axis and metaxylem lies towards the periphery. (b) Sap wood (Albernum) is the inner colored part of the wood of tree, composed of dead cells filled with resin, gums, tannins, etc., and is not suited for conduction. (c) Tracheid are single cell structures, elongated with tapering ends and shorter in size than vessels. Which of the above statements is/are correct?