The correct answer is A) the aide keeps confidential whatever happens in the classroom.
The action that represents professional behavior on the part of a teacher aide is "the aide keeps confidential whatever happens in the classroom."
A good and efficient teacher aide knows that it has to be prepared to confront any situation, good or bad. It is there to help and support the teacher when necessary. That is why it has to learn the lessons, understand the concepts in order to explain them, have a couple of good examples to support its arguments, and show the kind of professionalism and respect a teacher is expected to show in class.