I would like to suggest a feature (fi it doesn't already exist)

User is awarded 10 points for passing a quiz on response #1

5 points for response #2

1 point for response #3

0 points for response #4 to whatever

I like to the option to where the user is allowed multiple responses but i don't want to award them any points for retaking the same quiz over and over.   

Then, i would suggest the option to turn off multiple responses, only if the user passes the quiz.