The correct option is D Centripetal and centrifugal
Development of xylem in maize root is centripetal, in which protoxylem is formed away from the center it means near the pericycle and metaxylem is formed towards the center. This condition is called exarch.
Development of xylem in sunflower stem is centrifugal, in this type of development, 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.
So, the correct answer is "option A"