Moral is the lesson you learn from the story
The author of a book wants to make the reader feel what the topic of book is about. for example if the book is sad, the author wants the reader to feel those emotions.
The word that correctly completes the given sentence above would be driving. The complete sentence is: They will be driving to Chicago next week. The verb takes the -ing form, which is the simple future tense of the verb because the action indicates that it will be done some time in the future and is not yet started.
