Which tool selects an area using a "paint" motion and an adjustable round brush?

The Quick Selection Tool is designed to allow users to select areas of an image through a painterly motion with an adjustable round brush. This tool operates by analyzing the color and texture differences in the image to create a selection as you drag the brush over the area you want to select.

As you move the brush, it automatically detects the edges of objects, making it efficient for selections that may have irregular shapes. The size of the brush can be adjusted, providing flexibility in selecting broad or finely detailed areas. This attribute makes it very different from options like the Lasso Tool, which requires freehand drawing, or the Brush Tool, which is primarily used for painting and does not create selections on its own. The Spot Healing Brush, meanwhile, is used more for retouching and repairing images rather than selecting areas. Therefore, the Quick Selection Tool is the one that combines the adjustable brush feature with selection capabilities, making it the correct answer.