Answer:
It is an informal discussion because the people could participate without preparing in advance.
Step-by-step explanation:
An informal discussion is one that takes place without proper planning. This type of discussion is carried out suddenly to resolve situations without major impacts. None of the members of the informal discussion were submitted to rules, or needed to study and prepare for the discussion, as it ends quickly and only needs simple and direct answers. An example of this can be seen in the question above, where a group of friends quickly decide where they can rehearse for the school band. This discussion established between them was carried out without planning or regulations. In addition to being completed quickly and not having a big impact. This succeeds in proving that this situation is an example of informal discussion.