**Core Concept**
The question is testing the knowledge of intracranial tumours, specifically the most common type. This knowledge is essential for neurosurgeons, neurologists, and medical students to identify and manage these tumours effectively.

**Why the Correct Answer is Right**
The most common intracranial tumour is the **Meningioma**. Meningiomas arise from the meninges, the protective membranes surrounding the brain and spinal cord. They are typically slow-growing, benign tumours that can compress adjacent brain structures, leading to various symptoms. The exact cause of meningiomas is unknown, but they are thought to be related to genetic mutations and exposure to radiation. Meningiomas are often diagnosed incidentally on imaging studies or present with symptoms such as headache, seizures, or vision changes.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify a type of intracranial tumour.
* **Option B:** This option is incorrect as it refers to a type of tumour that is more common in the spine, not the brain.
* **Option C:** This option is incorrect as it refers to a type of tumour that is more common in the brainstem, not the most common type overall.

**Clinical Pearl / High-Yield Fact**
Meningiomas are often referred to as "benign" tumours, but they can still cause significant symptoms and disability due to their location and growth pattern. It's essential for clinicians to consider meningiomas in the differential diagnosis of patients with intracranial symptoms.

**Correct Answer: C. Meningioma. Meningioma**