Select the correct answer.
Which data set has the greatest spread for the middle 50% of its data?

A. {18, 13, 22, 17, 21, 24}

B. {17, 19, 22, 26, 17, 14}

C. {13, 17, 12, 21, 18, 20}

D. {18, 21, 16, 22, 24, 15}