Final answer:
A circular saw is used to cut wood across the grain quickly but does leave a rough edge. It is the correct answer among the provided options for the tool described.
Step-by-step explanation:
A saw that is used to cut wood across the grain and is known for being fast but leaving a rough edge is called a circular saw. Among the options provided, this type of saw fits the description of being suitable for such tasks. A circular saw utilizes a toothed or abrasive disc or blade to cut different materials using a rotary motion spinning around an arbor. While a circular saw indeed makes quick cuts, it does not leave as clean of an edge as some other types of saws, such as a table saw or miter saw which are typically used for more precise cuts. For the answer, c) Circular saw is the correct choice.