Which of the following reactions are exothermic?_x005F_x000D_  _x005F_x000D_ 1)   C + O2  → CO22)  2Mg + O2  → 2MgO3)  CuSO4 + 5H2O  → CuSO4.5H2O4)  All the above

• A. 1
• B. 2
• C. 3
• D. 4