**Core Concept**
Cerebral perfusion pressure (CPP) is the net pressure gradient causing blood flow to the brain. It is the difference between the mean arterial pressure (MAP) and the intracranial pressure (ICP) and is crucial for maintaining adequate cerebral blood flow.

**Why the Correct Answer is Right**
CPP is calculated using the formula: CPP = MAP - ICP. The MAP is the average pressure in the arterial system, while ICP is the pressure within the cranial vault. A balance between MAP and ICP is essential to ensure that the brain receives sufficient oxygen and nutrients. If CPP is too low, cerebral ischemia may occur, leading to damage or death of brain tissue.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a distractor referring to another concept. However, without knowing the specific content of option A, it is difficult to explain why it is incorrect.

**Option B:** This option might be referring to another component of cerebral hemodynamics. However, since it is not the correct formula for CPP, it is incorrect.

**Option C:** This option might be referring to another physiological parameter. However, it is not the correct definition of CPP, so it is incorrect.

**Clinical Pearl / High-Yield Fact**
One important clinical consideration is that CPP is a critical parameter in managing patients with head injuries or intracranial hypertension. Maintaining an optimal CPP is essential to prevent further brain damage.

**Correct Answer:** C. MAP - ICP.