**Core Concept**
Carbon dioxide (CO2) is transported in the blood through multiple mechanisms due to its low solubility in plasma. The body uses a combination of these mechanisms to maintain acid-base balance and ensure efficient CO2 removal from tissues.

**Why the Correct Answer is Right**
CO2 is transported in plasma as:
- **Dissolved form**: A small percentage of CO2 dissolves directly in plasma, which is approximately 7.5% of the total CO2 transported. This is due to its low solubility in plasma.
- **Carbamino compounds**: CO2 binds to hemoglobin, forming carbaminohemoglobin, which accounts for about 70% of the total CO2 transported. This reaction occurs when CO2 reacts with the amino groups of the hemoglobin molecule.
- **Bicarbonate**: The majority of CO2 (approximately 20-25%) is transported as bicarbonate (HCO3-), which is formed in the presence of carbonic anhydrase in red blood cells. CO2 reacts with water to form carbonic acid, which then dissociates into bicarbonate and hydrogen ions.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because while a small percentage of CO2 is dissolved in plasma, it is not the primary mechanism of CO2 transport.
**Option B:** Incorrect because, although carbamino compounds are a significant means of CO2 transport, they are not the only mechanism.
**Option C:** Incorrect because, although bicarbonate is a major form of CO2 transport, it is not the only mechanism.

**Clinical Pearl / High-Yield Fact**
In conditions of respiratory acidosis, the body compensates by increasing bicarbonate reabsorption in the kidneys, which can lead to metabolic alkalosis if not properly managed.

**✓ Correct Answer: D. All of the above**