The number of possible pairings of 2 objects selected from a set of x objects can be modeled by p(x) = 0.5x(x - 1). A

_Number of objects, x| Possible Pairings, p(x)
|__2__|___1___|
|_4___|6__|
|__9_. |___28___|
|13___|__78|

B

_Number of objects, x__|Possible Pairings, p(x)_
___2 |___1__)
5 |10
8 |28
12 |___66

C

_number of objects, x__|Possible Pairings, p(x)
___2 ___1
3 ___3
7 ___22
10 78

D

_Number of objects, x_| Possible Pairings, p(x)
2 ___1
4 ___6
10 ___44
12 ___66