**Core Concept**
Pseudo cholinesterase, also known as butyrylcholinesterase, is a plasma enzyme responsible for metabolizing certain ester-type local anesthetics and muscle relaxants, including succinylcholine. This enzyme plays a crucial role in the termination of neuromuscular blockade and the elimination of various anesthetic agents.

**Why the Correct Answer is Right**
The correct answer is a type of intravenous anesthetic that is metabolized by pseudo cholinesterase. Succinylcholine, a depolarizing muscle relaxant, is metabolized by pseudo cholinesterase in the plasma, which terminates the neuromuscular blockade. This enzyme-mediated metabolism is essential for the rapid elimination of succinylcholine and the prevention of prolonged apnea.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not relate to pseudo cholinesterase metabolism. Propofol, a widely used intravenous anesthetic, is metabolized by liver enzymes, not pseudo cholinesterase.
**Option B:** This option is incorrect because it is not a correct example of an intravenous anesthetic metabolized by pseudo cholinesterase. Midazolam, a benzodiazepine, is metabolized by liver enzymes, not pseudo cholinesterase.
**Option C:** This option is incorrect because it is not a correct example of an intravenous anesthetic metabolized by pseudo cholinesterase. Ketamine, a dissociative anesthetic, is metabolized by liver enzymes, not pseudo cholinesterase.
**Option D:** This option is incorrect because it is not a correct example of an intravenous anesthetic metabolized by pseudo cholinesterase. Fentanyl, a synthetic opioid, is metabolized by liver enzymes, not pseudo cholinesterase.

**Clinical Pearl / High-Yield Fact**
Pseudo cholinesterase deficiency can lead to prolonged apnea and muscle weakness due to the accumulation of succinylcholine. This condition is relatively rare but can be life-threatening in surgical settings.

**Correct Answer:** B. Succinylcholine.