Chọn C
C H ≡ C - C H = C H 2 + 3 B r 2 → C H B r 2 - C H B r 2 - C H B r - C H 2 B r C H 2 = C H - C H 2 - O H + B r 2 → C H 2 B r - C H B r - C H 2 B r C H 3 C O O C H = C H 2 + B r 2 → C H 3 C O O C H B r - C H 2 B r C H 2 = C H 2 + B r 2 → C H 2 B r - C H 2 B r