Excerpt from The Hidden History of Secret Passages Terri Roberts

For thousands of years, people have used secret passages and hidden rooms to protect precious belongings and save lives. These secret structures have played important roles throughout history by protecting royalty, hiding valuables, and fooling thieves.

Today, secret passages are still uncovered in many older homes and office buildings. These discoveries help historians understand more about the history of hidden passageways and about the people who built them.
What can you infer about the author's purpose in writing this passage?

A)It is to entertain the reader by telling jokes about the secret passages.
B)It is to describe in detail the way different secret passages were constructed.
C)It is to persuade the reader that the North deserved to win the American Civil War.
D)It is to inform the reader about the various uses of secret passages in different historical settings.