Please choose the correct ending to complete the given sentence: Health: [header] How to treat a corn or callus [title] Differentiate between a corn and a callus. [step] Corns and calluses are not the same thing, therefore the treatment approaches are different. [substeps] A corn can develop between the toes, has a core, and can be quite painful.

Ending1: It will take time to identify and treat a corn if it seems like a callus. In rare cases, a corn sac develops from a trauma of some sort. Ending2: A callus may grow from this core. Since corn and callus are the same thing, the treatment includes peeling and shaping it into a painless/oval-shaped callus. Ending3: Calluses usually get worse when seen on dogs but are commonly referred to as dog bites, because of the presence of extra skin when the corn is removed. A corn can also appear enlarged for shorter sessions than a callus, meaning more time breaks, but cannot be removed with techniques like veterinary emergency training or nail trimming. Ending4: Corns also develop along the tops of the toes, most often located just above a joint in the toe. Corns are categorized as hard, soft, or periungual.

Answer format: ending1/ending2/ending3/ending4