Final answer:
The car produced in 2017 should be counted in the GDP for 2017, the year it was produced, based on the definition of GDP which focuses on goods at their final stage of production within a specific year.
Step-by-step explanation:
According to the definition of GDP (Gross Domestic Product), it is a measure of the economic production of a country within a given year. It includes the current value of all final goods and services produced within the nation's borders. The car in question, produced in 2017 but sold in 2018, would be counted in the GDP for 2017, the year it was produced, not the year it was sold. This accounting method prevents the issue of double counting, ensuring that goods are counted at their final stage of production.