The displacement of an object can be calculated by finding the area under the velocity vs. time graph. In this case, the graph is a series of rectangles, so the area can be calculated by adding up the areas of each rectangle.

For the first second, the velocity is constant at 2 m/s, so the displacement is:

$$d = vt = (2 m/s)(1 s) = 2 m$$

For the next 2 seconds, the velocity is constant at 3 m/s, so the displacement is:

$$d = vt = (3 m/s)(2 s) = 6 m$$

Therefore, the total displacement of the object after 3 seconds is:

$$d = 2 m + 6 m = 8 m$$