The hydrosere succession is the succession in which a pond and the community are converted into a land community.
Various stages of hydrosere are:
1. Plankton stage: This is the pioneer stage of hydrosere. Different spores reach the water bodies and the organisms that appear are the minute autotrophes which are called phytoplanktons. E.g. diatoms, blue-green algae, green algae.
2. Submerged stage: Rooted plants in mud at the bottom grow densely. Submerged plants like Hydrilla , Vallisneria grow at this stage.
3. Floating stage: Floating leave anchored plants like Nymphaea appear in the shallow water.
4. Reed swamp stage: Amphibious plants like Saggitaria grow where the water body becomes shallow.
5. Sedge or Marsh meadow stage: The shores built up by the Reed swamp stage are invaded by sedge Carex and many grasses and herbs.
6. Woodland stage: The periphery of sedge meadow stage is invaded by Rhizome bearing shrubs.
7. Climax Forest: New trees invade the area and the tree and shrubs of woodland stage disappear.
Hence, the stage that comes just before the Sedge meadow stage is Reed swamp stage.
So, the correct answer is C.