Answer:
2√5
Explanation:
On the graphic, you see point Q is roughly between 4 and 4.5 units on the Y-axis.
So, all we have to do is find a value similar to that in the answer choices. So, let's look at the values:
2√5: 2 * 2.23 = 4.46... that's pretty much what we're looking for.
4√2: 4 * 1.41 = 6.4. Way too big.
2√13: 2 * 3.6 = 7.2, way too big.
8√2: We know that will necessary be way bigger than 4.5, so let's not even evaluate it.