This will work for both practice and test questions. The basic idea is to disable the default submit button and then show your custom submit button once the users has clicked on one of the options.
So you'll need to:
- Disable the default submit ('Question' ribbon tab > 'Disable Submit')
- Add a custom submit button (add a 'Submit Current Question' Player Control Action to any element)
- Add a "Show' Action to all your question 'Options' (choices) that show the submit button on click