The answer is C, the primary location for photosynthesis.
The palisade cells contains a lot of chloroplast, which contains a pigment called chlorophyll, which can trap light and turn them into energy source for the plant. This process is called photosynthesis. It is how the plant mainly make food and keep them growing.
Palisade cells are the main location for photosynthesis as they have the most chloroplast number usually in a plant. They can absorb sunlight efficiently thus photosynthesis is efficient.
So, the answer is C.
