**Core Concept**
The question is testing knowledge of the cerebral vasculature, specifically the arteries that supply the brain and the potential consequences of their injury. The anterior cerebral artery (ACA) is a crucial branch of the internal carotid artery (ICA) that supplies the medial surface of the brain, including the motor and sensory cortices.

**Why the Correct Answer is Right**
The ACA is prone to injury in the presence of a depressed skull fracture, particularly in the frontal region. This is because the ACA is superficial and lies close to the surface of the skull in this area. As a result, even a minor injury to the skull can lead to damage to the ACA, causing bleeding into the brain. The ACA is also more susceptible to injury due to its relatively fixed position and the presence of surrounding bone.

**Why Each Wrong Option is Incorrect**
* **Option A:** The posterior cerebral artery (PCA) is not typically injured in the presence of a frontal skull fracture, as it is located in the posterior fossa and is not as superficial.
* **Option B:** The middle cerebral artery (MCA) is also not typically injured in this scenario, as it is located in the Sylvian fissure and is not as superficial as the ACA.
* **Option D:** The internal carotid artery (ICA) is a major artery that supplies the brain, but it is not typically injured in the presence of a depressed skull fracture in the frontal region.

**Clinical Pearl / High-Yield Fact**
The ACA is often referred to as the "motor artery" due to its supply of the motor cortices, and injury to this artery can result in significant motor deficits.

**Correct Answer:** C.