Final answer:
In 2015, the average American likely had consumer debt closest to $15,000, reflecting only student loan debt, which rose to over $30,000 by 2019. The actual debt including all types was probably higher.
Step-by-step explanation:
In 2015, the average American's consumer debt significantly exceeded the options provided in the question. According to the Federal Reserve, the average amount of student loan debt for those who took out loans rose to over $30,000 by 2019. This figure does not include other forms of consumer debt such as auto loans, credit card debt, or mortgages, which would push the average consumer debt balance even higher. Therefore, it is likely the average consumer debt held by an American in 2015 was closest to option (c) $15,000, keeping in mind that this is a conservative estimate and the actual average debt was likely higher when considering all types of consumer obligations.