複選題3. 下列反應中，何者為氧化還原反應？ (A)$\text{Pb}{(\text{s})} + \text{PbO}{2(\text{s})} + 2\text{H}2\text{SO}4(\text{aq}) \longrightarrow 2\text{PbSO}{4(\text{s})} + 2\text{H}2\text{O}_{(\text{l})}$ (B) $\text{N}{2(\text{g})} + 3\text{H}{2(\text{g})} \longrightarrow 2\text{NH}_{3(\text{g})}$ (C) $\text{N}2\text{O}{4(\text{g})} + \text{H}2\text{O}{(\text{l})} \longrightarrow \text{HNO}{2(\text{aq})} + \text{HNO}{3(\text{aq})}$ (D) $\text{C}6\text{H}{12}\text{O}{6(\text{s})} + 6\text{O}{2(\text{g})} \longrightarrow 6\text{CO}{2(\text{g})} + 6\text{H}2\text{O}_{(\text{l})}$