First, we should find the square root of 68, which is 8.25. (an easy way to find the square root for numbers like this is to just use the calculator, as we can't automatically tell what it is; 68 isn't a perfect square number.) Since we know know the square root we can easily evaluate the questions!
Our answer is c), since the points only span from 0 - 8 and the square root of 68 is 8.25. Since 8.25 is greater than 8, it would be outside of the points and to the right of point Q.