The following is a hypothetical three step reaction that can be combined to an overall reaction. Determine if each of the following reactants appear in the overall reaction as a product, a reactant, or neither (meaning it was canceled out from the reaction entirely).

(1) A₃B₂ 2 AB + A

(2) AB + CD BC + D

(3) D + A AD

1. A3B2

2.AB

3. A

4. CD

5. BC

6. D

7. AD