What product is formed when cyclohexanone is oxidised?

• Correct answer
  A

  $\mathrm{HOOC} \cdot\left(\mathrm{CH}_2\right)_4 \cdot \mathrm{COOH}$
• B

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

  $\mathrm{CH}_3\left(\mathrm{CH}_2\right)_4 \cdot \mathrm{COOH}$
• D

  None of the above

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