A new advertising campaign featuring celebrities endorsing a brand of organic snacks led to a 15% increase in sales. Clearly, celebrity endorsements are highly effective in boosting sales for organic snack products. Which of the following questions, if answered, would be most useful in evaluating the argument?
✓ Correct Answer: Option D
To evaluate if celebrity endorsements are 'highly effective,' we need a baseline for comparison. Option D provides this by asking about previous campaigns, helping determine if the 15% increase is attributable to the celebrities or is typical for the brand/market.