**Core Concept**
Massive transfusion of citrated blood can lead to various complications due to the anticoagulant effect of citrate. Citrate binds to calcium ions, leading to hypocalcemia, which can cause neuromuscular excitability, arrhythmias, and other symptoms. This is a critical concept in transfusion medicine, as citrate can affect multiple bodily systems.

**Why the Correct Answer is Right**
Massive transfusion of citrated blood leads to citrate toxicity, which can cause hypocalcemia due to the chelation of calcium ions. This results in neuromuscular excitability, manifested as muscle cramps, tetany, and arrhythmias. Additionally, citrate toxicity can also lead to metabolic acidosis due to the accumulation of lactate, a byproduct of citrate metabolism. Furthermore, citrate can also interfere with the coagulation cascade, leading to bleeding complications.

**Why Each Wrong Option is Incorrect**
**Option A:** Not applicable, as this option is not provided.
**Option B:**
**Option C:**
**Option D:**

**Clinical Pearl / High-Yield Fact**
When transfusing citrated blood, it is essential to monitor calcium levels closely, as citrate toxicity can lead to severe complications. Additionally, citrate toxicity can be managed by administering calcium gluconate or calcium chloride to correct hypocalcemia.

**Correct Answer:** B. Hyperkalemia.