Left-most section:
.. You can tell from the point (3, 9) that the only viable choice is selection D.
Center section:
.. When you extend the graph to the y-axis, you see the y-intercept is 10. The slope is negative, so selection B is appropriate.
Right section:
.. The line goes up 3 grid points for each 2 to the right, so the slope is 3/2. In point-slope form the equation of that line can be written as
.. y = (3/2)(x -6) +4 = (3/2)x -9 +4 = (3/2)x -5 = (3x -10)/2 . . . . . selection C