The United States of America is the fourth largest country in the world, the third most populated and the wealthiest. It is made up of 50 states, 48 of which occupy the central part of the North American continent. Its population of 281 million is multiracial as a result of waves of immigrants arriving from Europe, Africa, Asia and South America. Its wealth is derived from its industrial output, its world-leading technologies and science, its extensive agriculture and forestry and vast natural resources including oil, coal and metal ores. It is estimated that something like 45 million tourists visit the United States each year, which makes tourism another very important contributor to the US economy.

Question: Its vast industrial output has made the United States the wealthiest nation on earth.
Options:
A. true, B. false, C. uncertain
Answer: "B"