Which tool in graphics programs is used to select a rectangular area of a layer or canvas?

The tool that is used to select a rectangular area of a layer or canvas in graphics programs is the Marquee tool. This tool is specifically designed for making selections, allowing users to define a specific shape—in this case, a rectangle—to isolate areas for editing, copying, or other actions.

The functionality of the Marquee tool is foundational in many graphic design tasks, as it provides precision in selecting portions of images for manipulation without affecting the surrounding areas. After an area is selected with the Marquee tool, you can apply various operations, such as cutting, copying, or applying effects, just to that selected area.

In contrast, the other tools mentioned serve different purposes. The Pencil and Brush tools are primarily for drawing and painting on the canvas, allowing artists to create and enhance visual content. The Clone Stamp tool is used for duplicating parts of an image from one area and applying them to another, which does not involve making selections in a rectangular or specific shape like the Marquee tool does. Hence, the Marquee tool stands out as the correct choice for selecting rectangular areas.