In the Redox Reaction 4Fe + 3 O₂ + 12HCl $\rightarrow$

In the redox reaction 4Fe + 3 O₂ + 12HCl $\rightarrow$ 4FeCl₃ + 6H₂O

A) HCl is the reducing agent.
B) O₂ is the substance oxidized.
C) Fe undergoes an oxidation number decrease of three units per atom.
D) More than one correct response.
E) No correct response.