**Core Concept**
The question tests the understanding of the classification of injuries in forensic medicine, specifically the distinction between primary and secondary injuries. Primary injuries occur at the moment of impact, whereas secondary injuries result from the victim's movement or interaction with the environment after the initial impact.

**Why the Correct Answer is Right**
The presence of extensive abrasions all over the body suggests that the victim was dragged or slid along the road surface, causing friction and abrasion to multiple areas of the body. This scenario is consistent with a secondary injury, which is caused by the victim's movement or interaction with the environment after the initial impact. The abrasions are not limited to the area of impact, indicating that the victim was not stationary at the time of injury.

**Why Each Wrong Option is Incorrect**
**Option A:** Primary Impact Injury is incorrect because primary injuries occur at the moment of impact, typically resulting in localized damage to the affected area. The extensive nature of the abrasions suggests a more complex mechanism of injury.
**Option B:** Secondary Impact Injury is incorrect because it implies a subsequent impact, which is not supported by the scenario. The abrasions are not indicative of a secondary impact, but rather of the victim's movement after the initial impact.
**Option D:** Postmortem artifact is incorrect because the presence of extensive abrasions suggests an injury that occurred before death. Postmortem artifacts are changes that occur to the body after death, and would not explain the presence of fresh abrasions.

**Clinical Pearl / High-Yield Fact**
In forensic medicine, the classification of injuries is crucial in determining the mechanism and sequence of events surrounding a traumatic incident. Remember that primary injuries are typically localized, whereas secondary injuries can result from the victim's movement or interaction with the environment after the initial impact.

**✓ Correct Answer: C. Secondary Injury**