Quizzes report FP but do not report FN when multiple answers are valid

[agaldran]

Just as the title shows, if a valid answer is not marked, this error will not be reported and we don't know we got it wrong, see below:

Above, the first option was also a valid answer, I did not mark it, but this was not repored as incorrect.

Thanks for the materials!

[rasbt]

Sorry, I totally missed that, and thanks for the note! We will be fixing/improving that!