**Core Concept**
Korsakoff's psychosis, a neurological disorder, is characterized by severe memory impairment and confabulation. It is often associated with thiamine deficiency, typically seen in chronic alcoholics. The condition affects the hippocampus and surrounding structures, leading to significant anterograde and retrograde amnesia.

**Why the Correct Answer is Right**
Confabulation is a hallmark feature of Korsakoff's psychosis. It involves the spontaneous generation of false memories, which are often elaborate and detailed, to compensate for memory deficits. This defense mechanism is an attempt to fill in gaps in memory, resulting in fabricated stories or events. Confabulation can be observed during bedside examination, where patients may provide false information about their past or present.

**Why Each Wrong Option is Incorrect**

* **Option A:** Astereognosis is a condition where a patient is unable to identify objects by touch. While it is a feature of certain neurological disorders, it is not characteristic of Korsakoff's psychosis.
* **Option B:** Apraxia refers to the inability to perform purposeful movements, often seen in patients with frontal lobe damage. It is not a defining feature of Korsakoff's psychosis.
* **Option D:** Hallucination involves perceiving something that is not present in the environment. While patients with Korsakoff's psychosis may experience hallucinations, it is not a characteristic bedside feature of the condition.

**Clinical Pearl / High-Yield Fact**
It is essential to differentiate Korsakoff's psychosis from other memory disorders, such as Alzheimer's disease. While both conditions involve memory impairment, Korsakoff's psychosis is characterized by a prominent confabulatory component, which is not typically seen in Alzheimer's disease.

**✓ Correct Answer: C. Confabulation**