What property is shown by the equation?




Column A


Column B








--- ABC


1.


(34 + 11) + 9 = (11 + 34) + 9





--- ABC


2.


25 + (–15 + 4) = (25 + (–15)) + 4





--- ABC


3.


–(–21 + 8) = 21 + (–8)





--- ABC


4.


–30 + (–16) = –16 + (–30)




A.


commutative property


B.


associative property


C.


opposite of a sum property