Official documents are documents in a specific format used by party and government agencies, enterprises, institutions, and social organizations in their official activities. They are used to convey and implement the party's and state's guidelines, policies, issue administrative regulations and rules, request and answer questions, guide and negotiate work. , An important tool for reporting situations and exchanging experiences. According to the definition, which of the following is documents? ["A is the chairman of a school's student union.", 'B is a book editor who writes an essay in his spare time.', 'C is the secretary of a county chief who wrote a speech on the standing committee for the county chief.', 'Ding is a staff member of a county-level institution. If there is something in the work, he must report to his superior.']