The correct answer is that " Monocots have straight veins whereas Dicot have branched veins.
Monocots leaves are long and thin with small inter-cellular spaces between them. On the upper surface of epidermis, monocots have bulliform cells. Monocot leaves have parallel veins and they have equal number of stomata on both sides of a leaf.
On the other hand, dicots have broad and branched vein structure on their leaves. Dicot leave shave lost of inter-cellular spaces and they have maximum number of stomata cells on the lower side of the leaf.