Answer:
The first graph is the trend line.
Explanation:
Trend Line
It's a line indicating the tendency of something being measured or evaluated. The trend line is meant to represent an approximation of a set of points of a measured magnitude.
We have three possible 'trend lines' to choose from. The second is not a line, so it's not the correct option. The third is not a line either, it's just a graph who joins all the measured points. It doesn't mark a trend.
The first graph is a trend line because it's a single line and can be used to represent the whole set of values .