Which of the following is submerged unattached plant?

Correct option is C

Correct Answer: (c) Ceratophyllum
Explanation:
→ Ceratophyllum (coontail) is a submerged, free-floating (unattached) macrophyte that does not root in sediment; it floats in the water column.
→ It forms dense underwater stands providing habitat and oxygenation.
Information Booster:
→ Hydrilla and Potamogeton are submerged but normally rooted; Vallisneria is rooted with ribbon leaves.
Additional Information (Other Options):
(a),(b),(d): rooted submerged species (attach to substrate).