The Associative Property of Addition states that the way in which numbers are grouped in addition does not change their sum. In mathematical terms, this property can be expressed as:
\[ (a + b) + c = a + (b + c) \]
From the options provided, the correct demonstration of the Associative Property of Addition is:
\[ (x + y) + z = x + (y + z) \]
However, since that option is not explicitly listed, we can analyze the closest expression in your options that relates to addition.
The option that correctly demonstrates the associative property using the context of addition is:
\[ (x + y) + z = x + (y + z) \]
However, I do not see that specific expression in the list you provided. Please let me know if you would like further assistance!