The ancient Egyptians were one of the first groups of people to use secret passages. The great pyramids were built to honor the rulers of this ancient civilization. When Egyptian leaders died, their people would place them in crypts, or tombs, deep inside the pyramids. These tombs were often filled with priceless treasures—items that the Egyptians believed their leaders would take with them to the next world. In order to prevent robbers from stealing these treasures, the Egyptians built secret passageways that led to the tombs. The designers also constructed fake tombs and deadly traps that would fool any would-be robbers.

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.

Which BEST identifies this passage as a source?

A) a reflective secondary source with firsthand interviews
B) an informative secondary source with historical information
C) a primary source with historical and biographical information
D) a primary source with original information and firsthand interviews