The scenario that can be represented by the line labeled 2 in the graph is walking back toward home at a constant speed.
In this context, a step-up line typically indicates that the movement in the graph is consistent and uniform in speed. Since the line is labeled with a steady increase in y-values corresponding to each minute in time, it suggests a consistent return towards home without any interruptions or changes in speed. The other options provided indicate varying speeds or changes in motion, which would not fit the description of the line labeled 2.