The correct answer is (b).
The range is the difference between the largest and smallest values in a set of data. In this case, the range is $70 – 20 = 50$.
The quartile deviation is a measure of how spread out the data is. It is calculated by finding the median of the lower half of the data and the median of the upper half of the data. The difference between these two values is the quartile deviation. In this case, the lower quartile is $25$ and the upper quartile is $41$. The quartile deviation is therefore $41 – 25 = 16$.
Option (a) is incorrect because the range is $50$, not $41$.
Option (c) is incorrect because the quartile deviation is $16$, not $22$.
Option (d) is incorrect because the range is $50$, not $41$, and the quartile deviation is $16$, not $11$.