Adding a check box.
You can insert Check Box Set interactions to be used like a Multi-Choice question, however, in this case the user can select (or check) one or more options.
The correct answer for each option within a set is defined, within the Interaction Editor, to be one of two states:
This option must be checked to be correct.
This option must remain unchecked to be correct
If none of the check boxes are selected, the question text receives the unanswered icon.
The following example illustrates how the feedback table can be used to customize the feedback text.
If the user checks only two of the options (options 1 and 3), the feedback will be:-