(c) endoplasmic reticulum
Ans : (d) chloroplasts.
The leaf and stem epidermis is covered with pores called stomata (sing., stoma), part of a stoma complex consisting of a pore surrounded on each side by chloroplast-containing guard cells, and two to four subsidiary cells that lack chloroplasts. The guard cells differ from the epidermal cells in the following aspects: The guard cells are bean-shaped in surface view, while the epidermal cells are irregular in shape. The guard cells contain chloroplasts, so they can manufacture food by photosynthesis (The epidermal cells do not contain chloroplasts). Guard cells are the only epidennal cells that can make sugar.