We start by ordering the values.
5, 7, 8, 10, 13, 14, 17, 17, 21
Now we find the median(middle number).
Median(b): 13
(I added (b) for "base" since we need to take more medians)
The median now divides this data into two halves.
Now we take the medians of the two remaining halves.
Median(Half1): 7.5
Median(Half2): 17
Mark off the minimum and maximum.
Min: 5
Max: 21
Now graph!
Your median(Half1) is incorrect, since your median for the first half is 9. Since our median for the first half is 7.5, the answer would be Answer Choice C.