Concept:Chlorophyll is the green pigment that traps light energy for photosynthesis. It is found inside chloroplasts, the organelles in green plant cells (mainly leaf cells).Solution:Photosynthesis takes place in the chloroplast, and the chlorophyll in it absorbs sunlight.Mitochondrion: the site of respiration (releases energy from food), not of light absorption.Vacuole: stores water, sap and wastes.Nucleus: controls the cell's activities and carries the genetic material.So chlorophyll is located in the chloroplast.Answer:Option A (chloroplast)