What is a common structural feature of homes built during the balloon frame era?

The correct answer highlights a characteristic of homes built during the balloon frame era, noting that these structures typically featured narrow doors. Balloon framing, which became popular in the late 19th century, involved the use of long, vertical wooden studs that extended the full height of the walls, allowing for quicker and more flexible construction. This method also often resulted in a more compact design, which included narrower doorways that were less suited to larger, more elaborate entries typically found in earlier architectural styles.

In homes from this era, the efficiency of materials and ease of assembly took precedence, affecting many design features, including doors. Therefore, the preference for narrower doors is a reflection of the pragmatic and streamlined approach that characterized balloon frame construction practices.