31. Choose the most appropriate sentence for the blank to ensure the coherence and cohesion of the passage. (A) The term "bank holiday" may seem unusual because these days are now associated with leisure rather than finance. (B) Before the law was passed, confusion sometimes arose when payments were due on holidays. (C) Although they are now taken for granted, bank holidays have a surprisingly complex history. (D) As bank holidays grew in popularity, they gradually became woven into the fabric of British culture.