Many gases are soluble in liquids. It depends on the nature of the solute, hence (a) is a correct option. The solubility of gases decreases with increase in temperature as the process of dissolution can be considered similar to condensation and heat is evolved too. The higher the temperature the more molecules escape the liquid phase. Hence, (b) is the correct option. The solubility of gases increases on increase in the pressure in the system, which is due to the increase in the number of gaseous particles per unit volume striking the surface of the solution to enter it. Hence, (c) is a correct option.

Hence the correct factors and options are (i) and (ii).