Internal Redundancy is described as:

• A. Continuity of load path from span to span
• B. If one member fails, load redistributed to other members
• C. The three main components of a bridge
• D. Creation of multiple load paths by elements that are mechanically fastened together

Answer: (D)

Internal redundancy is about creating multiple load paths inside a bridge through elements that are mechanically fastened together, so forces can be carried by alternative routes if part of the structure is damaged. This description directly captures how redundancy is built into the system—by tying together members so loads don’t rely on a single path. The other options describe related ideas but not the mechanism: continuity of load path across spans isn’t about multiple internal routes, redistribution after a member fails is a consequence of redundancy rather than its definition, and the option about the three main components of a bridge is unrelated.