**Core Concept**
The Fick principle is a method for measuring cardiac output by calculating the oxygen consumption of the body and the difference in oxygen content between arterial and mixed venous blood. This principle is based on the concept that oxygen consumption is directly proportional to the difference in oxygen content between arterial and mixed venous blood.

**Why the Correct Answer is Right**
The Fick principle formula is: Cardiac Output (CO) = Oxygen Consumption / (Arterial Oxygen Content - Mixed Venous Oxygen Content). In this case, Oxygen Consumption is 300 ml/min, Arterial Oxygen Content is 20 ml/100ml, and Mixed Venous Oxygen Content is 16 ml/100ml. Plugging in these values, we get: CO = 300 / (20 - 16) = 300 / 4 = 75 ml/min. However, we need the answer in liters per minute, so we convert milliliters to liters by dividing by 1000. Therefore, CO = 75 / 1000 = 0.075 L/min. To convert to a more clinically relevant unit, we multiply by 60 to get the cardiac output in liters per minute: CO = 0.075 * 60 = 4.5 L/min.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided, so we cannot evaluate it.
* **Option B:** This option is also not provided, so we cannot evaluate it.
* **Option C:** This option is not provided, so we cannot evaluate it.
* **Option D:** This option is also not provided, so we cannot evaluate it.

**Clinical Pearl / High-Yield Fact**
When using the Fick principle to measure cardiac output, it's essential to ensure accurate measurements of arterial and mixed venous oxygen content, as small errors can lead to significant inaccuracies in cardiac output calculations.

**Correct Answer:** .