Read the following proof of the polynomial identity a + b3 = (a + b)3 - 3ab( a + b). Step 1: a3 + b3 = a3 + 3a2b+ 3ab2+ b3 - 3ab(a + b) Step 2:03 + 63 = a3 + 3a2b+ 3ab2 + 63 - 3a26 - 3ab2 Step 3: 03 + b3 - a3 + 3a2b - 3a2b+ 3ab- - 3ab2 +63 Step 4: 03 + 63 = 43+ 63 Match each step with the correct reason. Step 3 Step 1 Step 4 Step 2 : Binomial Theorem :: Associative Property of Addition #: Distributive Property #: Combine like terms #: Associative Property of Multiplication #: Commutative Property of Addition # Commutative Property of Multiplication