Which of the following is a common tool for cutting hair?

Scissors are a fundamental tool in hair cutting because they allow for precision and versatility when shaping hair. They are designed with sharp blades that enable stylists to create various techniques, such as layering, texturizing, and blunt cuts. The varying lengths and shapes of scissors can also impact the outcome of the haircut, allowing stylists to personalize styles to fit clients' hair textures and lengths effectively.

Razor and hair clippers, while also tools used in hair cutting, serve different purposes. A razor is typically used for softer, more blended cuts and can create a different texture compared to scissors. Hair clippers are mainly employed for shorter hairstyles and are more suited for maintaining length rather than precise cutting techniques. The curling iron is not a cutting tool; instead, it is used to style hair by adding curls or waves. Thus, scissors are recognized as the most common and versatile tool for cutting hair in a professional setting.