The best description of condensation is (iv) The conversion of water vapor into its liquid state.
Explanation: Condensation is the process where water vapor (gas) turns back into liquid water. Option (iii), “The formation of clouds from tiny water droplets,” is a result of condensation, so while it’s related, it doesn’t fully define the process itself. Options (i) and (ii) describe the process of evaporation, which is the opposite of condensation.