Stefan wants to add (3 5/7 + 1 1/5 ) + 2 1/7 . He uses the Commutative Property to rewrite the problem. Which shows this step?

A.(3 5/7 + 1 1/5 + 2 1/7 )

B.3 5/7 + (1 1/5 + 2 1/7 )

C.(1 1/5 + 3 5/7 ) + 2 1/7

D.(2 1/7 + 1 1/5 ) + 3/5

commutative: a+b = b+a

so which choice fits that pattern?