Germany is the right answer.
Every year the World Trade Organization tracks how much each country sells to the rest of the world in merchandise trade, and for 2008 the country at the very top of that list was Germany, with exports totalling about $1.47 trillion. Germany's export strength came largely from high value manufactured goods such as cars, industrial machinery, and chemicals, which found strong demand in markets worldwide.
It is worth noting that this lead did not last much longer. In 2009, China pulled ahead of Germany and has held the top exporter position ever since, but that shift happened a year after the figure given in the question. The United States, despite having a huge economy, has typically run a trade deficit and was not the leading exporter. Russia's export basket was heavily weighted toward energy commodities like oil and natural gas, keeping its total exports far smaller than Germany's.
Given that the question specifically points to 2008 and the $1.47 trillion figure, the correct choice remains Germany.