Stop talking OR ELSE you won't understand the lesson A. If you stop talking, you won't understand the lesson B. If you keep talk
ing, you will understand the lesson C. If you keep talking, you won't understand the lesson D. If you don't stop talking, you will understand the lesson
because C said if you KEEP talking ,you won't understand the lesson so it means if you STOP talking.or else you won't understand the lesson so it means it was letter C.
