Answer:
It's B, 62.
First, you identify the median, (30,) and use this to identify the first and third quartiles. 2-18 are the first ranges, and 42-81 are the third.
You would need to split the ranges between the first quartile (9) and the third quartile (71).
The interquartile range is the difference between the first and third ranges, making it 62.