Here's why:

* Autotrophy is the ability to produce organic compounds (like sugars) from inorganic sources, using energy from sunlight.

* Chloroplasts are the sites of photosynthesis in plant cells. They contain chlorophyll, a pigment that absorbs light energy.

* This light energy is used to convert carbon dioxide and water into glucose (sugar) and oxygen, a process known as photosynthesis.

So, while the entire plant cell can be considered autotrophic, the chloroplast is the specific organelle that carries out the process of autotrophy.