If There Are 6 Means to Be Compared, Then How $\bar { X } _ { 2 }$

Multiple Choice

If there are 6 means to be compared, then how many possible different comparisons (such as $\bar { X } _ { 2 }$ compared to $\bar { X } _ { 3 }$ ) are there altogether?

A) 15
B) 30
C) 6
D) 36