Which of the following equations is balanced? (A) Fe + 3 0₂ --> 2 Fe₂O3 (B) 2 Fe + 3 0₂ ---> 2 Fe₂O3 (C) 4 Fe + 3 0₂ ---> 2 Fe₂O3 (D) 4 Fe + O₂ ---> 2 Fe₂O3 Select one: O a. A O b. B O c. C O d. D​