Which of the following describes an outline solid in drawing?

An outline solid in drawing is typically characterized by using a dark, defining line. This means that the line has a significant weight and is used to convey the shape and boundaries of an object clearly and vividly. Such lines help to emphasize the figure and can improve the impact of the design, making it stand out against the background and be understood easily by the viewer.

Using a dark line gives the drawing depth and clarity, allowing for easier identification of different elements within the graphic. While guiding lines or light lines may assist in creating the initial sketch, they do not provide the definitive visual presence that a dark line does. Similarly, a medium-stroke line can be more subtle and less defining, lacking the boldness required to effectively outline solid forms. A color-filled area represents a different concept entirely, as it pertains to filling shapes with color rather than outlining them. Thus, the choice of a dark, defining line is precisely what characterizes an outline solid in drawing.