When the mean, median, and mode of the list

10,2,5,2,4,2, x

are arranged in increasing order, they form a non-constant arithmetic progression. What is the sum of all possible real value of x ?

**Answer Choices**

A. 3

B. 6

C. 9

D. 17

E. 20

When the mean, median, and mode of the list

10,2,5,2,4,2, x

are arranged in increasing order, they form a non-constant arithmetic progression. What is the sum of all possible real value of x ?

**Answer Choices**

A. 3

B. 6

C. 9

D. 17

E. 20