The correct option is D Scyphozoa
The Scyphozoa is a class of Cnidaria which is sometimes referred to as the 'true jellyfish'. They do not possess skeletal structure. They have umbrella-shaped body with tentacles.
On the other hand, Hydrozoa is a class of individually very small, predatory animals, some solitary and some colonial, living in salt water.
Anthozoa is a class within Cnidaria which includes sea anemones.
Therefore, the correct answer is option C.