**Core Concept**
Non-depolarizing neuromuscular blockers (NDNs) are a class of pharmacological agents used to induce muscle relaxation by competitively blocking the nicotinic acetylcholine receptors at the neuromuscular junction. They are often used in surgical procedures to facilitate endotracheal intubation and provide muscle relaxation during surgery.

**Why the Correct Answer is Right**
The shortest acting non-depolarizing neuromuscular blocker is **Cisatracurium**. It has a rapid onset and short duration of action, making it ideal for procedures requiring brief periods of muscle relaxation. Cisatracurium is metabolized by Hoffman elimination, a chemical process that occurs in plasma and contributes to its short duration of action.

**Why Each Wrong Option is Incorrect**
* **Option A:** **Rocuronium** is a non-depolarizing neuromuscular blocker with a rapid onset of action but a longer duration compared to Cisatracurium. Its duration of action is approximately 30-60 minutes.
* **Option B:** **Vecuronium** is another non-depolarizing neuromuscular blocker with a moderate duration of action, approximately 30-50 minutes. It is not the shortest acting NDN.
* **Option D:** **Pancuronium** is a long-acting non-depolarizing neuromuscular blocker with a duration of action that can last up to 60-120 minutes. It is not suitable for procedures requiring brief periods of muscle relaxation.

**Clinical Pearl / High-Yield Fact**
When choosing a non-depolarizing neuromuscular blocker, consider the duration of action, onset time, and any potential interactions with other medications. Cisatracurium is a good option for procedures requiring brief periods of muscle relaxation, but its use should be carefully monitored due to potential cardiovascular side effects.

**Correct Answer:** C. Cisatracurium