The interquartile range (IQR) is $Q_3 - Q_1$.

• A: $85 - 30 = 55$
• B: $90 - 50 = 40$
• C: $135 - 105 = 30$
• D: $55 - 35 = 20$
• E: $125 - 85 = 40$

Data Set A has the greatest IQR of $55$.