1. **Problem Statement:** We need to find the locus of points equidistant from the line segments PR and QR in triangle PQR. 2. **Key Concept:** The locus of points equidistant from two line segments that meet at a point is the bisector of the angle formed by those segments. 3. **Explanation:** - The line segments PR and QR meet at vertex R. - Points equidistant from PR and QR lie on the angle bisector of angle PRQ. 4. **Conclusion:** The correct option is B: the bisector of angle PRQ. Thus, the locus is the angle bisector of angle PRQ.