Final answer:
The provided information does not include specific sales data for Whataburger in 2004; hence, it is not possible to ascertain the correct answer from the options given.
Step-by-step explanation:
The question pertains to the number of Whataburgers consumed in 2004. Unfortunately, the information provided does not contain specific data about Whataburger sales in that year. Therefore, it is not possible to accurately determine whether customers ate more than 5 million, 10 million, 15 million, or 20 million Whataburgers. To provide an accurate answer, one would need access to Whataburger's sales data or annual reports from 2004. In business and marketing, understanding consumer trends and product demand is crucial, but it requires precise and relevant data.