Paragraph: A small spherical monoatomic ideal gas bubble $\left(\gamma=\frac{5}{3}\right)$ is trapped inside a liquid of density $\rho_1$ (see figure). Assume that the bubble does not exchange any heat with the liquid. The bubble contains $n$ moles of gas. The temperature of the gas when the bubble is at the bottom is $T_0$, the height of the liquid is $H$ and the atmospheric pressure is $p_0$ (Neglect surface tension).
Question: As the bubble moves upwards, besides the buoyancy force the following forces are acting on it.

• A

  Only the force of gravity
• B

  The force due to gravity and the force due to pressure of the liquid
• C

  The force due to gravity, the force due to the pressure of the liquid and the force due to viscosity of the liquid
• Correct answer
  D

  The force due to gravity and the force due to viscosity of the liquid

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