The association is commensalism but it's a part of symbiosis...so both a and c should be correct answer...hermit crab gets protection from predators by stings of sea anaemone whereas sea anaemone doesn't significantly get benefitted(yes it do get benefitted by the food provided by hermit crab but that's not significant) so we can called it as commensalism symbiosis association

**Explanation:**

**Commensalism** is a type of symbiotic relationship between two organisms where one organism benefits while the other organism is neither harmed nor benefited. In this case, the sea anemone benefits by getting attached to the shell lining of the hermit crab, which provides it with protection and transport. The hermit crab, on the other hand, is not affected by the presence of the sea anemone.

Here is a detailed explanation of why the association between the sea anemone and the hermit crab is an example of commensalism:

1. **Sedentary Sea Anemone**: Sea anemones are sessile organisms that typically attach themselves to rocks, coral, or other stable substrates. They use their stinging tentacles to capture prey, and their body acts as a protective covering. In this association, the sea anemone benefits from attaching to the shell lining of the hermit crab as it provides a stable and mobile substrate for the sea anemone to live on.

2. **Hermit Crab**: Hermit crabs are mobile crustaceans that inhabit empty shells of other marine organisms. They use the shells as a protective covering and carry them around as they move. The hermit crab is unaffected by the presence of the sea anemone and does not benefit or suffer harm from it. The sea anemone simply attaches to the shell lining and does not interact directly with the hermit crab.

3. **No Harm or Benefit**: In commensalism, one organism benefits while the other organism is neither harmed nor benefited. In this case, the sea anemone benefits by gaining a stable and mobile substrate for attachment, but the hermit crab is not affected by the presence of the sea anemone. The hermit crab is not harmed or hindered by the sea anemone's presence.

4. **No Obligatory Relationship**: In commensalism, the association between the two organisms is not obligatory. This means that the sea anemone can attach to the shell lining of any available hermit crab, and the hermit crab can carry any other organism or remain unattached without any impact on its survival or well-being.

In conclusion, the association between the sedentary sea anemone and the hermit crab is an example of commensalism because the sea anemone benefits from the attachment to the shell lining, while the hermit crab is neither harmed nor benefited by the presence of the sea anemone.