As Rod points out, your suggestion will not work because in order to get a correct score the user should have to mark 'both' correct answers instead of one of them. Even partial scores, possible with MCQ, will not help.
Personally I would create a custom question slide. But to offer some suggestions, I need more information: do you want radiobuttons (which tell the user they should only use one answer) or checkboxes? Do you want to offer Retake/Review possibilities? Reporting to LMS will be possible but asks for some 'tweaks' (see links).
To get an idea of what I mean by custom questions:
http://blog.lilybiri.com/widgets-and-custom-questions-part-1
http://blog.lilybiri.com/report-custom-questions-part-1
And of course, the mastery widget of InfoSemantics would be a possibility, because it offers an easy way to have two OR scenarios.
Lilybiri