The correct option is A Chloroplast
The plant body consists of unbranched, uniseriate filaments. The cells of the filaments are arranged end to end. They are barrel-shaped or cylindrical in shape. The apical cell is somewhat rounded at its terminal end whereas, the basal cell is elongated and does not have chlorophyll. It is also called as the basal holdfast, which attaches the filament to the substratum. Hence the correct option is A.