Correct option is 
Algal forms which grow on the other aquatic plants are called epiphyte, e.g. Oedogonium.
Algae that grow within the plants are called endophytes, e.g. Anabaena.
Many algae grow on the shells of molluscs, turtles and fins of fishes and are called as epizoic algae, e.g. Cladophora.
Endozoic algae are found inside the body of aquatic animals, e.g. Zoochlorella.
