Okay so here is a working example (although primitive) it should illustrate what you’re wanting to happen.
There are 2 data fields that have been created named: Answers_list of type numeric and list enabled the second is Answers_correct of type numeric default value 0
From here you just need to use workflows to manipulate the data and display the correct information.
There are 2 main workflows both linked to the submit button. The first one looks compares the radio buttons value to that of the numbers stored in Answers_list, if it finds it in there it then modifies the current users Answers_correct field to + 1 and shows the popup box correct.
The second workflow compares the radio buttons value to the numbers stored in the Answers_list and if it does not find it in there it will then show the popup box wrong and does not increment the Answers_correct field.
There are some funny limitations to this which hopefully a more experienced user can help with and that is; I had to create the data fields within the current users this kind of sucks as it means every user will need a copy of the answer list (and why there is that button that says populate the answer list) ideally you would want to have a new data type containing a field with the list and just compare it with that.
Hopefully this helps!