Answer: B. Theme.
Explanation: the theme of a story or a written work is the underlying message that the author wants to send. In other words, it is the critical belief about life that the author trying to convey in the writing of a novel, play, short story or poem. When writing a literary adaptation, the setting, dialogue and characters of the story can change, but the theme should remain the same, because it usually is universal and trascends cultural barriers.