The slope is down to the right, so it is a negative slope.
The slope is the difference in y (the rise, or vertical difference) over the difference in x (the run, or horizontal difference).
Start at point (-5, 3).
Go vertically down until the y-coordinate is -2. That is 5 units down, or a rise of -5.
Now go horizontally to the right until the x-coordinate is 1. That is 6 units to the right, or a run of 6.
The slope is rise/run = -5/6.
Answer is choice D.