Please choose the correct ending to complete the given sentence: Pets and Animals: [header] How to file puppy nails [title] Use an emery board for humans if you need an easy solution. [step] Classic emery boards are available at your local pharmacy for a very low cost. Emery boards will work just fine for filing a puppy's nails, although you may go through more than 1 emery board in the process.

Ending1: [title] Use a filing tool made for dogs if you have one available. [step] Many pet stores will carry emery board-type tools created specifically for filing dog nails. Ending2: These boards will also kill your puppy's unwanted nails. [substeps] An emery board is great for filing, as it can save you many calories of cleaning in the long run. Ending3: [substeps] The component components are iron, which can help keep nails straight and bouncy while hiding the longer ones. In order to get the correct size nail shape, you'll need to use a emery board that is very big, roughly the same size as a nail in a nail salon. Ending4: [substeps] Do not use a pen, an emery board with a rubber base or other materials that can scratch the human's nails. These materials can damage the chihuahua's nails and put unnecessary stress on the nail.

Answer format: ending1/ending2/ending3/ending4