Which tool is primarily used to blend hair during a haircut?

The tool that is primarily used to blend hair during a haircut is often understood to encompass several options, and in this context, all the tools listed are relevant for different blending techniques.

Shears, for instance, are commonly used to create soft transitions and remove bulk from the hair, allowing for a blended finish. They can be utilized for point cutting, which softens the edges and blends layers seamlessly.

Clippers provide an efficient way to blend shorter lengths and are particularly useful for achieving fades and smooth transitions between varying lengths. The blending occurs when the clipper is used to gradually reduce length in a controlled manner, allowing for a smooth visual flow.

Razor cutting is another blending technique where the razor is used to create texture and soften edges. This method can produce a more diffused look at the hairline and is effective for layering.

Thus, the answer highlights that multiple tools can be employed for blending, making the choice "All of the above" accurate, as each tool has its unique application in achieving a blended haircut.