Billy and Alex worked together on their high school research papers, even though their teacher told them not to. They did not help each other that much, so they are certain it was not a big deal. A few days after turning their papers in, the teacher held them both after class. She said, "Billy, Alex, your papers were both very good, the best in the class. But because you had similar topics, I just wanted to make sure you did not collaborate. Did you?" Billy thinks for a moment. If the teacher knew how little they helped each other, she probably would not mind. But if he tells the truth, that will not matter. What would a Kantian deontologist say that Billy and Alex should do?