**Core Concept**
The infant is likely suffering from Shaken Baby Syndrome (SBS), a form of child abuse caused by violent shaking, leading to intracranial hemorrhage and other serious injuries.

**Why the Correct Answer is Right**
Shaken Baby Syndrome is characterized by the violent shaking of an infant, which results in the creation of a whiplash-like motion in the infant's head. This motion causes the brain to move back and forth within the skull, leading to the tearing of bridging veins and subsequent subdural hematoma. The most characteristic injury in SBS is the subdural hematoma, which can be detected on imaging studies such as CT or MRI scans.

**Why Each Wrong Option is Incorrect**
**Option A:** Skull fracture - While skull fractures can occur in infants who have been shaken, they are not the most characteristic injury associated with Shaken Baby Syndrome.
**Option B:** Rib fractures - Rib fractures can also occur in infants who have been abused, but they are not typically associated with Shaken Baby Syndrome.
**Option C:** Fractured long bones - Fractured long bones, such as the femur or humerus, are more commonly associated with physical abuse in infants, but not specifically with Shaken Baby Syndrome.

**Clinical Pearl / High-Yield Fact**
The "3 Ms" of Shaken Baby Syndrome are: Microscopic (bridging vein tears), Macroscopic (subdural hematoma), and Mortality (high risk of death due to brain injury).

**Correct Answer:** C. Subdural hematoma.