In which of the following reactions, organic product cannot show conformational isomerism?

• A

  ${\mathrm{H}}_2\mathrm{C}=\mathrm{C}{\mathrm{H}}_2\underset{\mathrm{alk}.{\mathrm{KMnO}}_4}{\overset{\mathrm{Cold}.\mathrm{dil}.}{\to }}$

• B

  ${\mathrm{H}}_3\mathrm{C}-\mathrm{CH}=\mathrm{C}{\mathrm{H}}_2\underset{{\mathrm{H}}^{+}}{\overset{{\mathrm{KMnO}}_4}{\to }}$

• C

  ${\mathrm{H}}_2\mathrm{C}=\mathrm{C}{\mathrm{H}}_2\underset{{\mathrm{CCl}}_4}{\overset{{\mathrm{Br}}_2}{\to }}$

• D

  $\mathrm{HC}\equiv \mathrm{CH}\underset{2.{\mathrm{CH}}_3\mathrm{Cl}}{\overset{1.1\mathrm{eq}{\mathrm{NaNH}}_2}{\to }}$