Canvas Data does not contain the responses of individual students.
The quiz_question_answer_dim gives the possible responses and particulars about the available questions, but it is not tied to a particular quiz_submission.
To get that information reliably, you should use the Submissions API where you get submissions and include[]=submission_history. This adds in the responses of the students.
Another other way to get results is to go into the Quiz and generate the student analysis report, but it's not very usable for certain types of questions (say multiple choice questions where there are commas in the responses).
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.