Answer: False.
Explanation:
A concave polygon is a polygon that has at least one interior angle greater than 180 degrees. This means that the polygon has a "cave" or indentation on its interior. However, the fact that a polygon is concave does not automatically mean that one of its diagonals will be drawn outside the polygon. Whether a diagonal is drawn inside or outside the polygon depends on the specific arrangement of the vertices, and cannot be determined solely based on the fact that the polygon is concave.