Answer: The correct answer is-
A-mesophyll.
Mesophyll cells are specialized cells present in the plant leaves and are significant for the process of most of the photosynthesis ( that is formation of food that is carbohydrate using carbon dioxide and water in the presence of sunlight).
These cells have chloroplast ( a green colored, membrane bound specialized organelle) where this mechanism of photosynthesis occurs.
Thus, option A) is the right answer.