Correct Answer - D
(D) An allylic halide is an alkyl halide in which . there are one or more halogen atoms on allylic carbons (carbon atoms next to doubly bonded C- atoms are allylic C-atoms). Except 4-bromobut- ene, all are allylic halides.
(A) `underset("4-Bromopent-2-ene")underset()(CH_(3)-overset(Br)overset(|)CH-CH=CH-CH_(2))`
(B) `underset("3-Bromo-2-methylbut-1-ene")underset()(CH_(3)-overset(Br)overset(|)CH-overset(CH_(3))overset(|)C=CH_(2)`
(C) `underset("1-Bromobut-2-ene")underset()(CH_(3)-CH=CH-CH_(2)-Br)`
(D) `underset("4-Bromobut-1-ene")underset()(Br-CH_(2)-CH_(2)-CH=CH_(2))`
(E) `underset("3-Bromo-2-methylpropene")underset()(overset(Br)overset(|)CH_(2)-overset(CH_(3))overset(|)(C)=CH_(2))`
