A student used a measure of spread to conclude that the movie ticket prices (in dollars) in set A were more spread out than those in set B. Which measure of spread did he use?

Set A: 10, 11, 11, 13, 15

Set B: 10, 11, 13, 13, 15

a) the range

b) the IQR

c) the standard deviation

d) none of the above