**Core Concept**
Blood transfusion complications often arise from the interaction between the transfused blood components and the recipient's physiology. Transfused blood can cause changes in electrolyte balance, acid-base status, and body temperature.

**Why the Correct Answer is Right**
Metabolic acidosis is not typically associated with blood transfusion. Transfused blood may cause metabolic alkalosis due to the citrate preservative, which is metabolized to bicarbonate by the liver. The citrate can also cause hypocalcemia, leading to hyperkalemia. Hypothermia can occur if the transfused blood is significantly cooler than the recipient's core temperature. However, metabolic acidosis is not a common complication of blood transfusion.

**Why Each Wrong Option is Incorrect**
**Option A:** Hyperkalemia can occur due to the breakdown of red blood cells during storage, releasing potassium ions into the plasma. This is a common complication of blood transfusion.
**Option B:** Citrate toxicity is a known complication of blood transfusion, particularly in patients with liver dysfunction or severe citrate metabolism disorders. Citrate can cause hypocalcemia, confusion, and even cardiac arrest.
**Option D:** Hypothermia can occur if the transfused blood is significantly cooler than the recipient's core temperature. This can lead to a range of complications, including coagulopathy and cardiac arrhythmias.

**Clinical Pearl / High-Yield Fact**
The citrate preservative in blood transfusions can cause hypocalcemia, which can lead to hyperkalemia and cardiac arrhythmias. This is a critical consideration in patients with liver dysfunction or severe citrate metabolism disorders.

**Correct Answer:**
✓ Correct Answer: C. Metabolic acidosis