I have a question where the student is supposed to click on a graphic. A text box appears with right/wrong answer. I want to limit to one attempt. How can I do this?

OK Sam.. So clicking the graphic or an optional graphic is the response.
On the graphic have an on click action that reflects the response. Two pop up would be OK, hide them at on display and then use a show/hide to make the appropriate one visible then fade out
You might also want to push the response to the score variable too