Given the task definition and input, reply with output. In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[header] How to take care of a freshwater snail [title] Look for a healthy snail. [step] Signs that your snail is healthy include a clean appearance and healthy coloring. Healthy coloring varies from species to species. <sep> (A) The snail's shell should be free of cracks. Most importantly, the snail should be active and moving about. (B) Seek help by consulting a national pet food service or if you live in a remote area. [title] Provide a wide variety of foods for snail owners. (C) Check for signs of dormancy in females. Observe if they have an inflexible shell. (D) If you see some of the following signs, it may be healthy to use a freshwater snail : [substeps] White coloring whipworms runny droppings even if the snail exhibits a disease [title] Keep the tank warm and dark. [step] Freshwater snails are notoriously cold-blooded.
A