exerciseModelClassID|exercise2.choice.ChoiceExerciseModel
submissionModelClassID|exercise2.choice.ChoiceSubmissionModel
solutionModelClassID|exercise2.choice.ChoiceSolutionModel
exerciseBodyClassID|exercise2.choice.ChoiceBody
prompt|
type|
numChoices|
choice_0|
choice_1|
choice_2|
choice_3|
answer_0|
answer_1|
answer_2|
answer_3|