**Core Concept**
The question is testing knowledge of anesthetic agents that are contraindicated in patients with raised intracranial pressure (ICT). The underlying principle is that certain anesthetics can increase ICT, worsen cerebral edema, or decrease cerebral perfusion pressure, making them unsafe in this clinical scenario.

**Why the Correct Answer is Right**
The correct answer is Propofol. Propofol is a commonly used anesthetic agent, but it can cause cerebral vasodilation, increase cerebral blood volume, and potentially worsen raised ICT. This is because Propofol causes a decrease in the mean arterial pressure and an increase in the cerebral metabolic rate, which can lead to increased cerebral blood flow and further increase in ICT. Additionally, Propofol can also cause a decrease in the cerebrospinal fluid (CSF) pressure, which can worsen the condition.

**Why Each Wrong Option is Incorrect**
* **Option A:** Thiopentone is actually used to decrease cerebral metabolic rate and cerebral blood flow, making it a safe option in patients with raised ICT.
* **Option B:** Ketamine can increase cerebral blood flow and metabolism, but it is not contraindicated in raised ICT and can be used cautiously in certain situations.
* **Option C:** Sevoflurane is a volatile anesthetic agent that can cause cerebral vasodilation, but it is not as potent as Propofol in increasing ICT and can be used safely in patients with raised ICT.

**Clinical Pearl / High-Yield Fact**
In patients with raised ICT, it's essential to choose anesthetic agents that decrease cerebral metabolic rate and cerebral blood flow, such as Thiopentone or Isoflurane. Propofol should be used cautiously or avoided in these patients.

**Correct Answer: D. Propofol**