Answer:
A. 15, 19, 26, 51, 18, 21
Explanation:
(A) contains an outlier which is 51.
An outlier is a value that is way bigger or way smaller than other values.
B, C, and D's group of numbers all look close together when it comes together, but option A stands out.
51 is way bigger than the other numbers in option A, so it is an outlier.
A. 15, 19, 26, 51, 18, 21
A is our best option, since the question asks us to choose the answer that has an outlier in it.