Answer:
Option A, Leaf
Step-by-step explanation:
Photosynthesis takes place in the chloroplast (a cell organelle that contains green pigment known as chlorophyll). Chloroplast is found in the cytoplasm of the cell of the plant/tree leaves. These chloroplast are found below the upper epidermis layer of leaves with in the palisade mesophyll layer that consist of elongated cells. The palisade layer lies near the top of the leaf surface.
Hence, it is the leaf in which photosynthesis takes place.