HF, JN
1) Examining this question, we can state that a tangent line is the one that "touches" the circle in one single point.
So, in this diagram we can state that the tangent line is HF
2) On the other hand, a secant line crosses the circle in two points at least. So the one that fits in this definition is the line defined by points JN
3) In Euclidian Geometry, a chord is a line segment that connects two points in a circle or curve. Examning the diagram again, we can state that KM is a chord.