Which of the following represents a clear leading question?

A leading question is one that is designed to guide the respondent towards a particular answer, often by embedding assumptions within the phrasing. The phrase "Shouldn't your brand be Acid Rain if it works best?" demonstrates this characteristic as it implies a presumption that the brand should be named "Acid Rain" and that it is the best option, thus steering the respondent towards agreement with that assertion.

This question invites a response that aligns with the idea that "Acid Rain" is inherently the superior choice, rather than allowing the respondent to provide an independent evaluation. In contrast, the other options present neutral inquiries that do not presume a specific outcome or judgment and allow for a variety of responses without suggesting one perspective is more valid than another. This distinction is crucial in identifying leading questions versus open-ended ones.