When showing off tourism became a purpose, it was expected that they would crowd together to famous attractions. In fact, tourism as a modern lifestyle can have diversified functions. If it is for education, you can take children to see the famous mountains and rivers , The ruins of the ancient city, to help them understand the country's history and cultural traditions; if it is for relaxation, you can go to the seaside, deep mountains, or choose a farmhouse in the suburbs nearby, and you can escape the hustle and bustle of the earth for a short time. Facing the purpose of tourism, look for The right place for vacation is the healthy concept of tourism, so that you can better enjoy the joy of tourism. The transformation and upgrading of the concept of tourism, the differentiation of the tourism market, the phenomenon of overcrowding may disappear, and the happiness in travel will also be more mellow. According to this text, what does “transformation and upgrading” of the tourism concept mean? ['Achieving diverse functions.', 'Rationally face the purpose of tourism.', 'Give practical meaning to tourism.', 'Enjoy the joy of travel.']