The correct option is
B The protoxylem develops towards the periphery & metaxylem towards the centre
In centripetal development of xylem, protoxylem is formed away from the center it means near the pericycle and metaxylem is formed towards the center. This condition is called exarch.
In centrifugal development of xylem, the protoxylem formed near the central axis and metaxylem is formed away from the center it means towards the periphery. This condition is known as endarch.