The correct answer would be option A. Monocot leaves have parallel veins; dicot leaves have a network of veins.
Monocots are the plants having only one cotyledon or seed with only one leaf also called monocotyledons. Dicots are the plants having two cotyledons or seed with two leaves.
Monocots and dicots have few characters that make them easily recognizable such as venation pattern: The arrangement of veins in a leaf is called the venation pattern; dicots have a reticulate or network of veins type venation, while monocots have parallel venation.
Thus, the correct option would be A.