The four abbreviations arranged in ascending order are w, x, y and z. The smallest three numbers average 23, while the largest three numbers average 29. What is the range of data?

The four abbreviations arranged in ascending order are w, x, y and z.

1.	The four abbreviations arranged in ascending order are w, x, y and z. The smallest three numbers average 23, while the largest three numbers average 29. What is the range of data?
A.	15
B.	24
C.	18
D.	21
Answer» D. 21