**Core Concept**
The assessment of disease severity in ICU (Intensive Care Unit) is crucial for determining the prognosis and guiding treatment decisions. This involves evaluating various physiological parameters to quantify the severity of organ dysfunction.

**Why the Correct Answer is Right**
The Sequential Organ Failure Assessment (SOFA) score is a widely used scoring system for assessing disease severity in ICU. It evaluates six organ systems: respiratory, cardiovascular, hepatic, coagulation, renal, and neurological. Each system is scored based on the degree of organ dysfunction, with a maximum score of 24. The SOFA score is calculated at admission and repeated daily to monitor the progression of disease severity. The score is useful in predicting mortality and guiding treatment decisions.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is likely incorrect as it does not specify a widely recognized scoring system for assessing disease severity in ICU.
* **Option B:** This option might be incorrect as it does not mention a scoring system that is commonly used in ICUs.
* **Option C:** This option could be incorrect as it does not provide a specific scoring system that is recognized in the medical community.

**Clinical Pearl / High-Yield Fact**
The SOFA score is a useful tool for predicting mortality in ICU patients. It is essential to calculate the SOFA score daily to monitor the progression of disease severity and adjust treatment plans accordingly.

**Correct Answer: C. APACHE II score. APACHE II score is a severity-of-disease classification system used in the intensive care unit (ICU) to quantify a patient's risk of death.**