Answer: The IQR is least affected by the long tail on the right of the graph.
The IQR is the inter-quartile range. It is the length of the box in the middle of the graph. Having the long tail on the right does not affect the box. Therefore, the IQR is not affected.
Interquartile range (IQR): it's the difference between the largest and smallest values in the middle 50% of a set of data. It is not affected by the long tail in the graph because its calculation only consider the central part of data.
Range: it’s the difference between the highest value and the lowest value in a data set. It is affected by long tails because consider the whole data
Median absolute deviation (MAD): it's the median of the absolute deviations from the data's median. It's moderate affected by long tails because atypical measures give greater absolute deviation that may cause a greater MAD.