ANS:D - less than 2.5

In structural engineering, a continuous beam is considered a deep beam if the ratio of effective span to overall depth (d/L​) is less than 2.5. Deep beams are characterized by their relatively large depth compared to their span, and they typically exhibit different behavior compared to slender beams. Due to their depth, deep beams often experience significant shear and may require special design considerations to ensure their structural integrity. So, the correct option is:

• less than 2.5