To determine which equation fits the relationship in the graph is best to determine the slope and y-intercept of the line.
The y-intercept is the point where the line crosses the y-axis. If you look at the graph said the point is (0,-3)
To determine the slope of the line you need to use two points, for example (4, 0) and (7, 2), and the formula:

Where
(x₁,y₁) are the coordinates of one of the points
(x₂,y₂) are the coordinates of the second point

The line that best represents the line is the last one (option D.)

Because its slope is

And its y-intercept is (0,-3)