Which tool is described as being flat, coarse, or double cut?

The tool referred to as being flat, coarse, or double cut is indeed a file. Files are hand tools used for fine shaping, smoothing, and removing material from various surfaces. The "flat" description indicates that files can be flat in shape, allowing for work on flat surfaces. The term "coarse" refers to the size of the teeth on the file, which determines how aggressively it cuts into the material; a coarser file will remove material more quickly than a finer one. Additionally, a "double cut" file features two sets of teeth arranged in opposite angles, allowing it to remove material more efficiently and quickly, making it suitable for more aggressive work.

In contrast, other options do not fit this description. A plane is primarily used for shaping wood or smoothing surfaces but does not have a coarse or double cut texture like a file. A saw is designed for cutting through materials and does not perform the smoothing or shaping function that files do. A chisel is used for carving or cutting but lacks the surface treatment capability of a file.