For any topic you select, you should not write off ‘the top of your head.’ Instead, take the time to research the topic, from different viewpoints when applicable, and formulate a cogent thesis. Anything presented as your opinion should be supported with evidence, (‘evidence’ in this instance doesn’t have to be scholarly research to ‘prove’ your argument, but instead, you should be able to point to specific news clip, social media post, article, or other artifact that you feel supports your point) and cited appropriately.