You can see the choices in English here:
https://tokyo2020.jp/en/games/emblem/evaluation/
I think you can vote here (or at least give feedback). It's hard for me to understand what you are supposed to do on this page as part of it is in Japanese.
https://www.emblem-comments.jp/
Let me know if you figure out what you are supposed to do there. I couldn't figure out how to vote for my favorite.
In my mind, it's clear.
A,B,C or D?
B is the best. What do you think?