Option 1 -> "Meddle to" is grammatically incorrect and not a standard English collocation.
Option 2 -> "Meddle about" is not the correct preposition used with the verb "meddle."
Option 3 -> "Meddle by" is grammatically incorrect and doesn't convey the intended meaning.
Option 4 -> "Meddle with" is the correct phrasal verb meaning to interfere or tamper with something.
Hence, Option 4: with -> The phrasal verb "meddle with" means to interfere with or tamper with something in an unwanted or unnecessary way. In this context, it perfectly conveys that the speaker is warning someone not to interfere with their papers -> correct