What property is shown?

–12 + (27 + 12) = –12 + (12 + 27)

a. associative property
b. commutative property
c. distributive property
d. opposite of a sum property

Commutative property is
a+b=b+a
we see the only difference between -12+(27+12) and -12+(12+27) is they are switched

so it would be commutative
it's not associatve because associative deals with moving parenthasees

Correct option B commutative property
The numbers are just switched, there is no difference in it.
a + b is same as b+a
Similarly,
-12 + 27+12 = -12 + 39 = 27
-12+12+27 = 27
See, no change takes place,just the positions of the numbers are changed

4should be the last one n=4