Symbols used in test choice shows answer as incorrect

dede

I've created a series of courses with no issues, except for one question where a question has odd characters in the choices. For example, "+2.00 -0.50 x 010 < > 2 ∆ base down "

No matter what I've tried, I can not get the final test results to show this answer as correct. Actually, once the choices are entered into the question, it doesn't even show the button as being depressed, when clicked. I even added a "Show" action to show a depressed button when selected.  I have tried the choices as images, with the question text set to white behind it. I've set the text to convert to image, etc.

Has anyone encountered this issue? It is surely a bug, but my client would like to see "Correct" or "Incorrect" in the results and obviously the test being scored correctly is a must. All show correct, but this. Many thanks in advance.