The correct option is D chloroplasts
The stomata exists in the epidermis layer, which is the outer layer found in the leaf and stem. The epidermal layer is a protective layer and hence is devoid of chloroplasts. However, the guard cells, although they exist in the epidermis, have chloroplasts and have the ability to photosynthesize. The ability of the guard cells to photosynthesize is linked to the mechanism of the opening and closure of stomata.