For similarity, in addition to models being geometrically similar to prototype, the following in both cases should also be equal

• A. Ratio of inertial force to force due to viscosity
• B. Ratio of inertial force to force due to gravitation
• C. Ratio of inertial force to force due to surface tension
• D. All the four ratios of inertial force to force due to viscosity, gravitation, surface tension, and elasticity