Final answer:
Without specific context, it's undeterminable who came up with the brilliant idea. Typically, group decisions are made through discussion and compromise, often resulting in a group collaboration outcome.
Step-by-step explanation:
In answering the question of who came up with a brilliant idea without specific context, it's impossible to provide a definitive answer. However, when considering how decisions are typically made within a group setting, the process generally involves collaboration and consensus. This question seems to touch on themes of group dynamics and decision-making. In a group without an official leader, which is known as an acephalous group, members frequently engage in discussion, propose different ideas, and eventually reach a compromise through collective agreement. In essence, these decisions are often the result of a group collaboration, as members share input and work towards a solution that satisfies the majority.