Which of the following is a common method to shape nails?

Using a file is a common and effective method to shape nails. Nail files come in various grits and materials, allowing for precise shaping of natural nails as well as artificial enhancements. The texture of the file can help create smooth edges and an aesthetically pleasing nail shape, making it essential for both manicures and nail art.

When using a file, it's important to file in one direction rather than a back-and-forth motion, as this minimizes the risk of splitting or damaging the nails. This method is widely used in the beauty industry due to its efficiency and ability to create a polished look.

Other methods mentioned, like using a fork or scissors, are not suitable or safe for nail shaping, while sandpaper, although it can shape nails, is not typically used due to its abrasive nature and potential to cause harm to the nail and surrounding skin.