Although this is not (not yet?) specifically provided for in the questions edit form, it is possible to add html tags to answers (Choices) e.g. in the multiple choice questions. One can need formatting tags (bold, italics), nolink tags* or even inserting images in those choices.
When the question is displayed to the student, the HTML tags are correctly evaluated and the formatting / nolinks / images are displayed as expected.
However, on the Review and Statistics pages, the raw HMTL code is displayed, which does not look so nice. See attached example (images).
Joseph
* tag needed pending the fix of bug MDL-24996.