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Solution
The correct option is A A- Echinarachnius (sand dollar), B- Asterias (starfish), C- Echinus (sea urchin) The common sand dollar is the name of Echinarachnius parma. It is the common species of the sand dollar. The shells of these sand dollars are round, flat and disc-like. The entire shell is also covered with maroon-colored spines. The spines are movable. Asterias is commonly known as starfish. They are found in shallow waters. They have five arms which are also known as tube feet. The organism has calcareous endoskeleton. The upper surface of the organisms shows spines. There is presence of ossicles and plates on the upper surface of the body. Echinus esculentus is commonly known as sea urchin. This is a species of marine invertebrates. They belong to the family of Echinidae. They are found in deep waters. They have an oval-shaped body.