**Core Concept**
Intraocular pressure (IOP) is a critical parameter in ophthalmology, and various factors can influence its regulation. The autonomic nervous system, particularly the parasympathetic and sympathetic branches, plays a significant role in controlling IOP through the ciliospinal center and the ciliary ganglion. Anesthetics with specific properties can affect IOP by altering the autonomic tone.

**Why the Correct Answer is Right**
The correct answer is **C. Succinylcholine**. Succinylcholine is a depolarizing muscle relaxant that can cause an increase in IOP due to its ability to stimulate the sympathetic nervous system. This stimulation leads to an increase in the release of catecholamines, such as adrenaline and noradrenaline, which in turn cause vasodilation and increase the IOP. This effect is more pronounced in patients with pre-existing glaucoma.

**Why Each Wrong Option is Incorrect**
**Option A:** Halothane is a general anesthetic that can actually decrease IOP due to its ability to relax the ciliary muscles and decrease the production of aqueous humor.

**Option B:** Propofol is a short-acting sedative-hypnotic agent that can decrease IOP due to its vasodilatory effects and ability to decrease the production of aqueous humor.

**Option D:** Nitrous oxide can actually decrease IOP due to its ability to increase the choroidal blood flow and decrease the production of aqueous humor.

**Clinical Pearl / High-Yield Fact**
It's essential to note that succinylcholine-induced IOP increase is more pronounced in patients with pre-existing glaucoma, and this effect can be mitigated by administering anticholinergic agents, such as atropine or glycopyrrolate, before administering succinylcholine.

**Correct Answer: C. Succinylcholine**