3.以溴乙烷为原料制取 1,2- 二溴乙烷,下列转化-|||-方案中最好的是 () 。-|||-A.CH3CH2B r HBr溶液 CH2-CH2-|||-Br Br-|||-B. (H)_(3)C(H)_(2)Brxrightarrow [UND]({Br)_(2)}C(H)_(2)BrC(H)_(2)Br-|||-C.CH3CH2Br NaOHM溶液 (H)_(2)=!=!= C(H)_(2)xrightarrow ({H)_(2)}-|||-(H)_(3)C(H)_(3)xrightarrow [UND]({Br)_(2)}C(H)_(2)BrC(H)_(2)Br-|||-D.CH3CH2 Br NaOH醇溶液 (H)_(2)=C(H)_(2) 溴 水-|||-CH2BrCH2 Br