Broadly speaking, collective memory is the memory of one's past by a group with its own specific cultural cohesion and unity. This group can be a political religious group, a regional cultural community, or a nation or a This kind of memory can be scattered, fragmented, verbal, or centralized, official, written, and can be a recollection of a recent event or a retrospective of ancient ancestors' deeds. According to the above definitions, Which of the following are collective memories:. ["The Legend of Dayu's Water Control Widely Spread in China.", 'A documentary promoting local tourism resources in a city.', 'Compilation of documents by a government agency on a job.', 'Textbooks on the history of neighboring countries in a university in China.']