Answer: C) 56 gallons.
In 1970, the average American consumed roughly 28 gallons of soda. That number has since doubled to 56 gallons of soda a year. With the increase in soda consumption, Americans have also increased their consumption of high fructose corn syrup. According to the USDA, in 2001 the average American consumed almost 63 pounds of the sweet stuff made from corn.
Source: SF Gate