This would be C) Commutative Property of Addition.
Why?
Simply because the numbers are in reverse order after the equal sign.
See how "π+ 10" turns into "10 + π?"
This very simply switches the number order.
Another example of the commutative property of addition is here :
Ex : 8 + 6 = 6 + 8
See how I very easily just switched the numbers?
So, your answer is C) commutative property of addition.
~Hope I helped!~
