Answer:
2
Explanation:
When the problem talks about fastest rate, it means where is the line the steepest.
At the first point, the population is growing pretty slowly; the line is pretty flat.
When you get to the second point, the line is suddenly really steep. (You don't need to know this yet, but you can also say that the slope of the line is very steep; and the slope at the second point is greater than the slope at the first, third, or fourth points.)
At the third point, the line isn't growing that much again; it's at the top of a mountain, which can be pointy but you can't really call it steep.
Finally, the fourth one is actually going down, so obviously the population is not growing at all.
