**Explanation:**

A ruler is a straight, flat, and long object typically made of wood, plastic, or metal. It is used to measure or draw straight lines. The edge of a ruler is a straight line that is used to create various types of lines and line segments.

**Line Segment:**
A line segment is a part of a line that has two endpoints. It is a straight path between two points. The edge of a ruler can be used to draw line segments by placing one endpoint at a specific position and then extending the ruler to the desired length. The resulting line will be a line segment.

**Ray:**
A ray is a straight path that extends infinitely in one direction from a given point. The edge of a ruler cannot draw a ray directly because it has a fixed length. However, by placing one endpoint of the ruler at a specific position, the edge of the ruler can be used to draw a line segment that extends in one direction indefinitely, resembling a ray.

**Curve:**
A curve is a line that continuously bends without any sharp corners. The edge of a ruler, being straight, cannot be used to draw curves. Curves require tools like compasses or other curved instruments.

**Line:**
A line is a straight path that extends infinitely in both directions. The edge of a ruler can be used to draw a line by placing one endpoint at a specific position and extending the ruler in both directions. The resulting line will be a straight, infinite line.

Therefore, the correct answer is option C) line segment. The edge of a ruler can be used to draw line segments, but not rays, curves, or lines.