**Core Concept**
Staphylococcus aureus produces a toxin that causes food poisoning, leading to gastrointestinal symptoms such as vomiting. This toxin acts on the autonomic nervous system, specifically the vagus nerve, to induce vomiting.

**Why the Correct Answer is Right**
The mechanism of Staphylococcus aureus-induced vomiting is attributed to the toxin's action on the vagus nerve, which triggers the vomiting reflex. This is a classic example of a peripheral stimulus causing vomiting. The toxin acts directly on the vagus nerve, leading to the release of acetylcholine, which in turn stimulates the vomiting center in the brainstem. This action is mediated by the parasympathetic nervous system, specifically the vagus nerve.

**Why Each Wrong Option is Incorrect**
**Option A:** Stimulation of cAMP is not directly related to the mechanism of Staphylococcus aureus-induced vomiting. While cAMP is an important second messenger in cellular signaling, it is not involved in the toxin's mechanism of action.

**Option C:** Stimulation of cGMP is also not relevant to the mechanism of Staphylococcus aureus-induced vomiting. cGMP is another important second messenger, but it is not involved in the toxin's action on the vagus nerve.

**Option D:** Ganglioside GM receptors are involved in the action of some bacterial toxins, but they are not the primary mechanism of action for Staphylococcus aureus-induced vomiting. The toxin's action on the vagus nerve is a more direct and specific mechanism.

**Clinical Pearl / High-Yield Fact**
Staphylococcus aureus food poisoning typically presents with symptoms within 2-6 hours after consumption of contaminated food or milk products. The toxin's action on the vagus nerve makes this a classic example of a peripheral stimulus causing vomiting.

✓ Correct Answer: B. Vagal stimulation