The correct option is B Adaxial
A dorsiventral leaf is a leaf which is present at an angle to the main axis and perpendicular (normal) to sunlight direction. It has two distinct surfaces, the upper or inner or adaxial or ventral and the outer or abaxial or dorsal.
The xylem has protoxylem lying towards the upper side, i.e., adaxial surface. The metaxylem is present in lateral sides. Phloem is present towards lower epidermis with protophloem on abaxial surface.
Thus, the correct answer is option A.