Which tool is commonly used to push back cuticles?

The correct choice is a cuticle pusher, as this tool is specifically designed to safely and effectively push back the cuticles during a manicure. The purpose of the cuticle pusher is to help maintain the health of the nail and surrounding skin by allowing better access to the nail plate and creating a clean, polished appearance. These tools often have a flat end for gently pushing back the cuticle and sometimes a pointed end for cleaning under the nail.

In contrast, a nail file is used to shape and smooth the edges of the nails, not to manage cuticles. A buffer is intended to smooth the surface of the nail and add shine, while a brush is more useful for painting or cleaning nails. Thus, the cuticle pusher stands out as the essential tool needed for cuticle care.