Option C (Evaporation) is correct because the textbook explicitly states that 'Evaporation is a process by which water is transformed from liquid to gaseous state.' This directly matches the question asking about transforming liquid into vapour. Option A (Condensation) is incorrect because it is the opposite process - 'the transformation of water vapour into water.' Options B and D are not relevant to the transformation of liquid into vapour as per the given context.