This display issue is related to the zoom setting of the web browser. If the browser has been zoomed in, parts of the test question may be off the screen.
To remedy this situation, reset the zoom of the browser. You may need to quit the browser and sign in again after adjusting the zoom. Try pressing the Control button and the 0 (zero) keys simultaneously or the command and 0 keys.
See the support documentation for your web browser for more information on resetting the zoom if those keys did not solve the problem.