**Core Concept**
Intracranial hypertension (ICT) or increased intracranial pressure (ICP) is a critical condition where the pressure within the skull exceeds the normal range. This can be caused by various factors, including trauma, tumors, infections, and hydrocephalus. The Monro-Kellie doctrine explains that the sum of the volumes of intracranial contents (brain, cerebrospinal fluid, and blood) remains constant, and any increase in one component must be compensated by a decrease in another.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of ICT caused by a specific condition. **Option C** is correct because obstructive hydrocephalus, characterized by the accumulation of cerebrospinal fluid (CSF) in the ventricles, leads to an increase in ICP. This occurs due to impaired CSF circulation and absorption, resulting in a build-up of pressure within the cranial vault. The increased ICP can cause various symptoms, including headache, nausea, and visual disturbances.

**Why Each Wrong Option is Incorrect**
* **Option A:** Incorrect because cerebral edema, although it can cause ICT, is not the direct cause listed in the question. Cerebral edema is a complex condition involving fluid shifts within the brain, leading to increased ICP.
* **Option B:** Incorrect because cerebral vasospasm, a condition characterized by the narrowing of blood vessels in the brain, can lead to decreased blood flow but is not a direct cause of ICT.

**Clinical Pearl / High-Yield Fact**
In the context of ICT, it's essential to remember the Monro-Kellie doctrine, which states that the sum of the volumes of intracranial contents remains constant. This concept is crucial for understanding the pathophysiology of ICT and for making informed clinical decisions.

**Correct Answer:** C. Obstructive hydrocephalus.