An alkene $\mathrm{X}\left(\mathrm{C}_4 \mathrm{H}_8\right)$ exhibits geometrical isomerism. Oxidation of A with $\mathrm{KMnO}_4 \mid \mathrm{H}^{+}$gave Y . On heatirg sodium salt of Y with a mixture of NaOH and CaO gave Z . What is Z ?

• A

  $\mathrm{CH}_3 \mathrm{CH}_3$
• B

  $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_3$
• C

  $\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{CH}_2 \mathrm{CH}_3$
• Correct answer
  D

  $\mathrm{CH}_4$

Hence, the correct answer is option: 'D'.