What I would like to know here: is there really the need for this?
It would be great if you could express yourself on this one.
As always, here is my point of view as a user.
It is often said that a feature would be implemented if the demand is sufficient. In reality, it seems that other factors, equally important if not more important, affect the implementation of a given feature. These factors are whether a developer has
the time to implement the feature, based on his/her workload and the technical difficulty in implementing the feature, practical feasibility and usefulness of the feature and whether the developer thinks himself that the feature is relevant or not.
Probe other developers and users to know if they think a new feature is relevant should not be used mechanically, i.e. no vote, no implementation, but rather as one of the decision criteria. When in doubt about a feature, the survey can be used simply
to obtain opinions.
Quiz forum users will not express themselves for a feature that does not attract their attention. This does not mean there is no need. If, instead of asking on this forum, you google "all of the above and none of the above for multiple choice questions",
you get 144 millions results. In other words, this feature must be relevant. The lack of response in this forum simply means that there is no objection to the implementation of the feature.
In summary, the feature is not technically difficult to implement, as you point out in the tracker, it is easy to show that the feature is used universally in multiple choice questions, and no one has objected. The last criterion is your judgment.
In my opinion, this feature is certainly useful and I think you should implement it. In the meantime, your lecturer and other users can use the script I mentioned in my previous post. 
