Read the text and answer the question. Peak Oil, Inc. operates an oil refinery in Washington state. In 2018, the company imported $1 billion worth of crude oil from Canada. Out of that crude oil, the company produced $1.5 billion worth of gasoline and $1.5 billion worth of fuel oil. Peak Oil exported and sold all of the gasoline it produced in Canada and it sold all of the fuel oil domestically. The company did not produce or import any other products.
Under the output expenditure model of determining gross domestic product, what value did Peak Oil contribute to the United States' net exports in 2018?
O $0.5 billion
O $1.5 billion
O $2 billion
O $3 billion