Author: Rossiani Wijaya
MDL-39488 Lesson Module: Fixed PHP error matching question, if one or more options have not been selected.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=9705bfa84f5b22b3a2bc8862962fe51077675c8d
http://github.com/moodle/moodle/commit/9705bfa84f5b22b3a2bc8862962fe51077675c8d
+ 2.3 en [noanswer,mod_lesson]