**Core Concept**
The **baroreceptors** play a crucial role in regulating blood pressure through the **baroreflex** mechanism, which involves the activation or inhibition of various neural pathways to maintain **blood pressure homeostasis**. This reflex is essential for short-term blood pressure regulation. The baroreceptors are stretch-sensitive receptors located in the walls of the **aortic arch** and **carotid sinuses**.

**Why the Correct Answer is Right**
When **baroreceptors** are stretched due to an increase in blood pressure, they discharge, sending signals to the **central nervous system**, specifically to the **nucleus tractus solitarii** in the **medulla oblongata**. This discharge leads to the inhibition of **sympathetic outflow** and the activation of **parasympathetic outflow**, resulting in a decrease in blood pressure. The inhibition of sympathetic outflow reduces the release of **norepinephrine**, leading to decreased heart rate and vasodilation.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because the discharge from baroreceptors actually leads to the inhibition of sympathetic outflow, not its activation.
**Option B:** Incorrect as the discharge does not directly stimulate the sympathetic nervous system.
**Option D:** Incorrect because while parasympathetic outflow is activated, the question asks about inhibition.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the baroreflex mechanism is crucial for maintaining blood pressure homeostasis, and its dysfunction can lead to **orthostatic hypotension** or **hypertension**. Understanding this mechanism is vital for managing patients with blood pressure disorders.

**Correct Answer: C. Sympathetic nervous system**