It is required to identify the graph of the inequality y≤-3.
To do this, draw the boundary line of the inequality first, and then shade the appropriate region.
Change the inequality sign to the equal sign to get the equation of the boundary line:
This is a horizontal line that passes through -3 on the y-axis.
Since y=-3 is included in the inequality, then the line should be a thick line.
Next, shade the region that contains the numbers that are less than y=-3, that is, below the line.
Hence, the correct graph is shown below: