A suitable tool for cutting curves is the...

The suitable tool for cutting curves from the provided options is the compass, keyhole, and coping saw. Each of these tools is designed specifically for making intricate cut patterns required when working on projects that involve curves or detailed shapes.

A compass saw is particularly useful for making curved cuts in wood and has a long, narrow blade that helps access tight spaces. A keyhole saw, also known as a drywall saw, is effective for making internal cuts, allowing for cutting out shapes within a material. A coping saw has a thin, flexible blade that can easily navigate curves, making it ideal for woodworking projects that require precision.

While the circular saw, jigsaw, and reciprocating saw are versatile tools useful for various cutting tasks, they are generally better suited for straight cuts or more significant and less intricate work. The jigsaw, in particular, can cut curves but is not as fine-tuned as the coping saw. Therefore, among the choices given, the tools specified in the first option are the most appropriate and precise for cutting curves.