In option A, if expression is simplify with out using associative property then addition of 4/9 and -2/9 is easy, as compare to addition 6 and 4/9. So no need to apply associateive property to option A.
In option B, 60 and 40 can be easily add as compare to 40 and -27 so this expression do not need to apply associative property.
In option C, the expression is easier to simplify if 5/2 and -1/2 is added, which is possible if associative is apply to the expression.
[tex]\begin{gathered} (2+\frac{5}{2})+(-\frac{1}{2})=2+(\frac{5}{2}-\frac{1}{2}) \\ =2+(\frac{5-1}{2}) \\ =2+2 \\ =4 \end{gathered}[/tex]
Thus option C use associative property to make the simplification easier.
Answer: Option C.
