The temperature and pressure at the summit of Mt . Everest is $-30^{\circ} \mathrm{C}$ and $0.27 \times 10^5$ $\mathrm{N} . \mathrm{m}^{-2}$, respectively. The corresponding values at sea-level are $27^{\circ} \mathrm{C}$ and $1 \times 10^5$ $\mathrm{N} . \mathrm{m}^{-2}$. Considering air to be an ideal gas, the ratio between the molecular number density at the summit of NTt. Everest to that at sea level is closest to

• A

  $1: 30$
• B

  $81:100$
• C

  $27: 100$
• Correct answer
  D

  $1: 3$

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