**Core Concept**
The formation of a haemoglobin derivative due to the reaction of CO2 with blood is a key process in maintaining acid-base balance and transporting carbon dioxide. This process involves the binding of CO2 to haemoglobin, forming a stable complex that is then transported to the lungs for exhalation.

**Why the Correct Answer is Right**
The reaction of CO2 with blood forms carbaminohaemoglobin, a stable complex that is formed when CO2 binds to the N-terminal amino group of the haemoglobin molecule. This reaction is facilitated by the presence of carbonic anhydrase, an enzyme that catalyzes the conversion of CO2 to bicarbonate. The binding of CO2 to haemoglobin is an important mechanism for transporting CO2 from tissues to the lungs, where it can be exhaled.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because it is not a known haemoglobin derivative formed due to the reaction of CO2 with blood.
* **Option B:** This option is incorrect because it is not a specific haemoglobin derivative, but rather a general term for the binding of CO2 to haemoglobin.
* **Option D:** This option is incorrect because it is not a known haemoglobin derivative formed due to the reaction of CO2 with blood.

**Clinical Pearl / High-Yield Fact**
Carbaminohaemoglobin is an important buffer in the blood that helps to maintain acid-base balance by binding to excess CO2. This process is critical in preventing respiratory acidosis, which can occur when CO2 levels become too high in the blood.

**Correct Answer: C. Carbaminohaemoglobin**