Step: 1
4 + (5 + 3), (4 + 5) + 3 illustrates same sum. But grouping of addends is changed.
Step: 2
According to associative property of addition, changing the grouping of the addends does not change the sum.
Step: 3
So, 4 + (5 + 3), (4 + 5) + 3 illustrates associative property of addition.
Correct Answer is : Associative property of addition