Most likely in your question object, there is a answer parameter. So you have an object Question with the attributes question and answer. The answer could be an enumeration with the values a, b and c to make it a multiple choice question.
To answer questions, an option would be to create an attribute userAnswer in the question object. this userAnswer should be of the same type as the answer attribute in the Question object.
Now give the user write rights to the userAnswer attribute, and create a form where you retrieve the question you want answered in a dataview (from xpath or using a datasource microflow). Then add a button with a microflow behind it, which checks the userAnswer attribute and the answer attribute. If it is wrong, the user should recieve some feedback that the answer is wrong.
You could take a look at the questionnaire module.