question/type/ddmarker
From MoodleDocs
Drag and drop marker questions allow for multiple markers to be placed onto an image and the positioning of each marker to be assessed.
Drag and drop marker questions differ from Drag and drop onto image questions in that there are no predefined areas on the underlying image that are visible to the student.
This is a question type created and maintained by the Open University.
More documentation
More http://labspace.open.ac.uk/mod/oucontent/view.php?id=470268§ion=5.5.1 documentation is available on the Open University's OpenLearn site.