Choice D is not the correct answer. Point L is equally distant from J and K. In other words, JL = LK. If two friends lived at points J and K, then point L would be a good meeting spot as they would travel the same distance. Point N has the same properties as point L does (with regard to being equally distant from J and K). It is not correct to say that LJ = JN.
The answer is actually choice C. Segments JL and KL need to be constructed using a straightedge.
Otherwise, these segments are not going to be shown and you cannot use them. A segment is simply a straight line between two endpoints. Two triangles form (triangle JNL and KNL) to help with the proof, so it's very beneficial to draw in these segments. It might help to use a different color pen, or lightly draw the segment using a faint pencil mark to erase later.