C# - Select and display a random group box each time a button is clicked

I am making a quiz game and one of my levels is going to be fill in the blanks. In this level I have laid out 10 different group boxes with a label and text boxes in each of them. I would like to be able to randomly select a different group box each time the next button is clicked. The next button will appear after the check button has been clicked to check the users answers in the text boxes and change the score variable. I need to ensure that the same group box doesn't show up twice. Any help would be greatly appreciated. Thanks, Ryan.