Author: Sam Marshall
Choice: MDL-20440 Added completion support to Choice (mark completed when user makes choice)
http://git.moodle.org/gw?p=moodle.git;a=commit;h=bc499733f8a0f34bbcc4d88d382d9046e8f332eb
http://github.com/moodle/moodle/commit/bc499733f8a0f34bbcc4d88d382d9046e8f332eb
+ 2.0 en [completionsubmit,mod_choice]