In January 2021, the city of San Francisco purchased a GM truck for $40,000. The truck was produced in Detroit in November 2020 at a cost of $30,000. The purchase of the truck in January 2021 _____ .

A.) increases 2020 GDP by $30,000

B.) increases 2020 GDP by $40,000

C.) increases 2021 GDP by $10,000

D.) increases 2021 GDP by $70,000