What architectural feature does the Old Bank of the United States prominently feature?

The Old Bank of the United States prominently features wrought iron railings, which are characteristic of many historical buildings in New Orleans, showcasing the city's unique architectural style. Wrought iron was a common material used in the 19th century for decorative purposes, allowing for intricate designs that added elegance and charm to the structure. The railings not only serve a functional purpose but also enhance the aesthetic appeal of the bank, reflecting the artistry of the time and contributing to the overall historic character of the area.

Other choices may represent features found in various architectural styles or other buildings, but they do not specifically highlight the defining characteristics of the Old Bank of the United States in the way that wrought iron railings do.