According to the definition of tourism activities by the World Tourism Organization, the temporary nature of tourism activities means that the continuous stay time must be within (　).

Answer: C

No matter what type of tourism activity, it has the characteristic of temporary nature. The intuitive manifestation is that tourists must return to their usual place of residence after completing the entire tourism activity. They will neither stay too long in the place they visited nor settle there permanently. Taking international tourism as an example, according to the regulations of the World Tourism Organization, this temporary nature means that the continuous stay of tourists in the destination they visit does not exceed 12 months. If this time limit is exceeded, the visitor will be regarded as a permanent immigrant or temporary immigrant and will no longer be included in the tourist statistics.