Since quizzes are created by humans and not robots there could be an error with an answer.
Bear in mind that just because you think you have an answer right it doesn't mean you are correct. The case sensitivity or punctuation of an answer does not matter but there could be various reasons the answer is not what you think, for example:
- The answer is a persons full name rather than their abbreviated name
- Some quiz answers might not be the person but some other identifying information such as their number in a team, or a film they starred in
- Spelling is a common issue, spell check the answer using the Google form to the right of every quiz just to make sure