How is pollination carried out in water plants?

(N/A) In many aquatic plants,flowers emerging above the water surface are pollinated by wind or insects.
$(b)$ In some aquatic plants,pollination occurs below the water surface,which is called $Hypohydrophily$ (e.g.,$Ceratophyllum$).
$(c)$ In other aquatic plants,if pollination occurs on the surface of the water,it is called $Epihydrophily$ (e.g.,$Vallisneria$).