Final answer:
Option C. The most likely source of bleeding in a 70-year-old man with a headache and large parietal scalp hematoma after a fall is the middle meningeal artery, which is commonly associated with epidural hematomas as a result of head trauma.
Step-by-step explanation:
When considering the source of bleeding in a 70-year-old man presenting with a headache and a large parietal scalp hematoma after a fall, the non-contrast computed tomography scan would likely show evidence related to the type of hemorrhage. Given the location, trauma, and the clinical scenario, the most likely source of bleeding is the middle meningeal artery. This is because the middle meningeal artery is often involved in epidural hematomas, which can occur following a head injury when fracture of the temporal bone can lead to tearing of the artery.
The other options listed such as bridging veins, meningeal veins, and the superior sagittal sinus, typically are involved in different types of intracranial hemorrhages. Bridging veins would be more likely to cause a subdural hematoma, which usually presents with a crescent-shaped bleed that can cross sutures but not dural attachments. The superior sagittal sinus could be involved in a venous sinus thrombosis, not usually a hematoma from trauma. Meningeal veins, too, are less likely to be the source of bleeding in trauma when compared to the middle meningeal artery.