Answer:
b. Message
Explanation:
In literature, the theme is the message or lesson that a story conveys about a topic. One literary work may have more than one themes or messages, and they are not directly stated in the story so we, the readers, usually have to think them through.
For example, in the Cinderella story, one of the topics is "dreams", and one of the themes that it conveys is "Dreams can come true.", which it's a message that can also apply to life.