Answer:
The U.S. GDP increases by $200.
Explanation:
Gross domestic product or GDP is the value of finished goods and services made within a country in terms of money.
Here as given that the American soldier living in US purchased a $100 MP3 player made in China by a Chinese firm, this will not increase the GDP as the firm is Chinese.
But when he purchased fruits from a local farmers market, then he is contributing to the GDP of US.
Hence, U.S. GDP increases by $200.