To identify \( \angle LNM \) in the diagram you described, let's analyze the points:
- \( O \) is the center of the circle.
- Points \( L \), \( N \), and \( M \) are on the circumference of the circle.
The angle \( \angle LNM \) is formed by the points \( L \) and \( M \) that lie on the circle, with \( N \) being the vertex on the circumference.
Since this angle is formed by two points on the circle ( \( L \) and \( M \) ) while the vertex is on the circle as well ( \( N \) ), this angle is classified as:
an inscribed angle.
So the correct response is:
an inscribed angle.