The answer is B.
Explanation:
The min and max are 6 and 30, which is the same for all of the choices.
We need to find the median, which since there's an even number of elements we take the mean of the two elements in the middle (eg 20 and 22), which gives us 21. So the middle whisker will be on 21, so we know the answer is B or D.
Next, we need to find the upper and lower quartile. For these, we take the median again, but this time it's the median of the upper and lower halves (split by our median of 21). So, for the lower half, we have 6, 7, 9, 9, and 20. Since there's an odd number of elements this time, we just take the middle element, which is 9, so that's the lower whisker.
Then we do the same for the upper quartile. The upper half (above 21) is 22, 26, 28, 29, and 30. Since the number of elements is odd again, we just take the middle element, which is 28, so that is the upper whisker.
Plot the lower and upper whiskers and the median and you get graph B.