Enable the possibility for a teacher or moderator (not student) to answer (briefly) in the tool
There should be a mechanism that allows the teacher of a course to answer a question (briefly) directly in the questions' view.
Currently, it is only possible to answer "yes" and "no". In many cases the questions cannot be answered in this way and it is not always necessary to discuss each non yes-or-no question in class.
Use a speech bubble icon ("add_comment") and place it to the left of the Correct button. Use a "comment" button in student's view if the teacher has added a comment.