The internal and external diameters of a hollow cylinder are measured with the help of vernier callipers. Their values are $4.23\pm 0.01\mathrm{cm}$ and $3.87\pm 0.01\mathrm{cm}$ respectively. The thickness of the wall of the cylinder is

• A

  $0.36 \; \pm \mathrm{ }0.02 \mathrm{cm}$
• B

  $0.18 \; \pm \mathrm{ }0.02\mathrm{cm}$
• C

  $0.36\; \pm \mathrm{ }0.01\mathrm{cm}$
• Correct answer
  D

  $0.18\; \pm \mathrm{ }0.01\mathrm{cm}$ 

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