Which of the following is adapted for an aquatic habitat?

The correct option is D Vallisneria
Vallisneria is a freshwater aquatic plant. It is an angiosperm plant which is adapted to the aquatic environment. Pollination takes place through hydrophily. In Vallisneria, the female flower appear on the surface of the water as they have a long stalk. The pollen grains released by the male flower reaches to female flower for fertilisation through water currents. These are submerged plants which spreads by runner.

So, the correct answer is option B.