Which of the following are applicable to the term 'Carnival'?

A. It became important through the work of the Russian theorist Mikhail Bakhtin.

B. It means the way in which popular humour subverts official authority in classical, medieval and renaissance texts and culture.

C. It overturns the established hierarchy and sets up a popular and democratic counter-culture.

D. It brings out the serious elements in literature.

E. It is used as a critical tool for interpretation of poetry.

Choose the correct answer from the options given below.