This template is designed to make the Memrise kind of multiple-choice tests, which always expect a single correct choice, with the answers being submitted as soon as any of the buttons is clicked (there is additional functionality for alternative answers, but it still accepts any single one of the correct choices as a right answer).
Of course, one still could change the template to work with sets of choices instead of a single choice, but that is not a small change, and would require modifying all the scripts for how the choices in the test randomized, how the buttons are pressed, how the answer is stored and retrieved, and how its correctness is evaluated.