Answer:
B. (2+5) + 7 = 2 + (5+7)
Explanation:
The Associative Property of Addition states that:
(a+b) + c = a + (b+c).
Or, any three or more numbers added together will have the same sum no matter how they are grouped.
Answer choice B is the only choice that exhibits this, and so, B is the answer.
Hope this helps!