Final answer:
Fracturing the scaphoid bone would cause tenderness in the floor of the snuff box, which is a symptom often associated with this type of fracture. The correct option is C.
Step-by-step explanation:
The structure which, if fractured, would present with tenderness in the floor of the snuff box, is the scaphoid bone. The snuff box is an anatomical area located on the lateral aspect of the wrist. Tenderness in this area is a classic sign of a scaphoid fracture.
The scaphoid is one of the carpal bones of the wrist and is located in the proximal row of carpal bones. It is the most commonly fractured carpal bone, usually resulting from a fall onto an outstretched hand. Due to the poor blood supply to this bone, healing can be slow, and there is a risk of bone necrosis and degenerative joint disease.