**Core Concept**
Peripheral muscle relaxants act by blocking the action of acetylcholine at the neuromuscular junction (NMJ) or interfering with the release of acetylcholine from motor neurons. This leads to muscle relaxation without affecting the central nervous system.

**Why the Correct Answer is Right**
The correct answer works by competing with acetylcholine for receptor sites at the NMJ, thereby reducing the amount of acetylcholine available to bind and trigger muscle contraction. This mechanism is specific to the neuromuscular junction, making it a peripherally acting muscle relaxant.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is a centrally acting muscle relaxant that works by affecting the central nervous system, causing sedation and muscle relaxation. It does not act peripherally at the neuromuscular junction.
**Option B:** This option is incorrect because it is a depolarizing muscle relaxant that works by activating nicotinic receptors at the NMJ, leading to muscle contraction followed by prolonged relaxation. It is not peripherally acting.
**Option C:** This option is incorrect because it is a combination of drugs, one of which is a centrally acting muscle relaxant, and the other a peripherally acting muscle relaxant. This option is not a single peripherally acting muscle relaxant.

**Clinical Pearl / High-Yield Fact**
Peripheral muscle relaxants can cause muscle weakness and paralysis, which can lead to respiratory failure if not monitored properly. Always assess the patient's respiratory status before administering these medications.

**Correct Answer:** B.