The correct answer is B) Although the economy was prosperous on the surface, there were serious underlying problems.
The statement that is true about the American economy of the 1920s is "Although the economy was prosperous on the surface, there were serious underlying problems."
We are talking about a prosperous time in the United States called "The Roaring 1920s." This was a time of good economic situation in which people bought many things, mostly on credit. They bought cars, furniture, and electronics. However, although the economy was prosperous on the surface, there were serious underlying problems due to the debt that was generated.
Things changed on October 29, 1929, when the US stock market crashed, starting the Great Depression. Millions of Americans lost their jobs, companies had to close, and banks went into bankruptcy.