Plugin site: http://calendarscripts.info/watupro/
The plugin is a premium version of the free Watu which can be found at the official repository. WatuPRO comes with the following premium features:
- single-choice, multiple-choice and open end questions
- randomize questions and answers
- pull a number of random questions from quesitons bank
- set time limit to take the test
- printable certificates assigned to selected grades
- export results as CSV
- integrated with Wordpress user authorization system.
The plugin price is $47 and includes 1 year of free upgrades and free support.