Position of protoxylem & protophloem in leaf respectively -

A dorsiventral leaf, which is present at an angle to the main axis and perpendicular (normal) to sunlight direction, has two distinct surfaces, the upper or inner or adaxial or ventral and the outer or abaxial or dorsal. The upper and lower epidermis are composed of compactly arranged, barrel-shaped cells without any Intercellular spaces and a cuticle on both layers. Veins represent the vascular bundles that are found irregularly scattered in the spongy parenchyma of mesophyll with the largest and the oldest one at centre, termed as midrib vein. The xylem has a protoxylem lying towards the upper side i.e., the adaxial surface and metaxylem on lateral sides. Phloem is present towards the lower epidermis with protophloem on the abaxial surface. 
Hence, the correct option is B.