I am excited to announce that g(Math) for Forms will now allow you to use handwriting entries as multiple choice options. Just click on the Create handwriting entry icon in any part of the option and you can handwrite an entry.
I just published the update and it will be live soon in the Chrome store and should automatically update for you if you already have g(Math) for Forms installed.
I am working on rolling out handwriting entries as a question type in the next week or so, keep an eye out for them!