**Core Concept**
The limbus is the border between the cornea and the sclera in the eye. Intravitreal injections involve injecting medication into the vitreous humor, the gel-like substance inside the eye. The location of the injection is critical to avoid damaging the retina or other structures.

**Why the Correct Answer is Right**
The safest site of intravitreal injection is approximately 3-4 mm from the limbus, specifically in the inferotemporal quadrant. This location allows for easy access to the vitreous humor while minimizing the risk of retinal detachment or other complications. The inferotemporal quadrant is chosen because it is farther away from the optic nerve and macula, reducing the risk of damage to these critical structures. The injection site is also typically chosen to be at a 30-degree angle to avoid direct injection into the retinal vessels.

**Why Each Wrong Option is Incorrect**
**Option A:** Injecting too close to the limbus (1-2 mm) increases the risk of ciliary body injury and subsequent glaucoma.
**Option B:** Injecting 2-3 mm from the limbus may still be too close to the optic nerve and macula, increasing the risk of damage to these structures.
**Option D:** Injecting 4-5 mm from the limbus may be too far from the desired location, increasing the risk of missing the target and causing complications.

**Clinical Pearl / High-Yield Fact**
When performing intravitreal injections, it is essential to use a 1-mL syringe and inject 0.1 mL of medication at a time, while constantly monitoring the intraocular pressure and the patient's vitreous humor for any signs of complications.

**✓ Correct Answer: C. 3-4 mm**