Here's an updated file that should fix the issues you're having:
dropbox.com/scl/fi/ir6vaib3h30owrvpenmsr/Mapabox_MB.c3p
In event 9 all txt_answerNew.number were being set to the same value.
In 10/11 all instances of list_answer_input, txt_option and txt_answerNew were being acted on rather than those sharing the button number - you needed to pick the instances with the same number as the button.
If you want to simplify your events, instead of picking instances using a shared number value I would consider adding these objects into a container together - that way, when you pick an instance the instances in its container are automatically picked.