George, a student of mine, requested a private meeting with me in my office. George was concerned about his grade. He couldn't understand why his grade was so much lower than a few of his friends in the class. I explained he was either not putting enough effort into the class or that he may need some guidance on how to properly study for a law class. George became angry and started yelling at me and then accused me of taking bribes from other students to improve their grades. His claim is false, but he kept repeating it. What, if anything, could I sue George for? What result?