**Core Concept**
Korsakoff psychosis, also known as Korsakoff syndrome, is a chronic memory disorder caused by a lack of thiamine (vitamin B1) in the brain. This condition is often associated with chronic alcoholism, but it can also result from other conditions that lead to malnutrition, such as gastrointestinal disorders or cancer.

**Why the Correct Answer is Right**
Korsakoff psychosis is characterized by a profound anterograde amnesia, where the individual is unable to form new memories. This is due to damage to the hippocampus and surrounding structures, particularly the mammillary bodies, which are involved in memory formation and consolidation. The lack of thiamine disrupts normal neurotransmitter function, particularly the glutamatergic system, leading to neuronal damage and death.

**Why Each Wrong Option is Incorrect**
**Option A:** Wernicke encephalopathy is a different condition from Korsakoff psychosis, characterized by confusion, ataxia, and ophthalmoplegia, and is also caused by thiamine deficiency. However, Wernicke encephalopathy can progress to Korsakoff psychosis if left untreated.
**Option B:** Alzheimer's disease is a progressive neurodegenerative disorder that affects memory, but it is not caused by thiamine deficiency and has a distinct pathophysiology.
**Option C:** Delirium tremens is a severe form of alcohol withdrawal that can cause confusion and hallucinations, but it is not a chronic memory disorder like Korsakoff psychosis.

**Clinical Pearl / High-Yield Fact**
Korsakoff psychosis is often associated with a "confabulation," where the individual fills in gaps in their memory with fabricated information, which can be a useful clinical clue to diagnose the condition.

**Correct Answer:** C.