Chara and Nitella are:

Correct option is B

Correct Answer: (b) Submerged macrophytes
Explanation:
→ Chara and Nitella are charophyte algae that grow fully submerged, anchoring on sediments and forming dense underwater vegetation.
→ They provide habitat, oxygenate water and influence nutrient cycling.
Information Booster:
→ These plants are indicators of clear, less eutrophic waters and can stabilize sediments.
Additional Information (Other Options):
(a) Floating-leaved: e.g., Nymphaea.
(c) Emergent: e.g., Typha.
(d) Free-floating: e.g., Eichhornia.