B. 28 meters
You can see that the side opposite of 8 meters are all different sizes, but all three lengths, if you line them all up together, add up to 8 meters. So the two sides add up to 16 meters. Now the other two sides. You can apply the same thing that was said about the 8 meters to the 6 meters side. And then the other side is 3 meters, so you can find the missing length by doing 6-3 = 3 meters (or just see that it also equals six and you can just skip that).
So, now you have 8+8+6+6 (or 3+3, depending on which way you did it) = 28 meters.
