If the u. s. population in 1970 was approximately 200 million people, what was the approximate population by 2006?

In 2006, the population of the US was about 298 million according to the US census. For a large and powerful country this is a rather small population compared to say China with its approximate 1.2 billion people which is finally able to challenge the US for apparent economic hegemony in the world now. In the mining sector, it is China which is responsible for much of the consumption of metals so it affects the price of metals quite a lot too. On the other hand, the US with relatively few people has quite a high output of goods.

I’m pretty sure that the answer is b.