Answer:
The second picture.
Explanation:
A line of best fit should be placed where around half of the points are above the line and about half of the points are below the line.
In the first graph, only 3 points are above the line; 7 are below the line.
In the second graph, 5 points are above the line; 5 points are below the line.
In the third graph, 7 points are above the line; 3 points are below the line.
In the fourth graph, 3 points are above the line; 7 are below the line.
The one closest to half and half is the second graph.