**Core Concept**
The best irrigating fluid during Extracapsular Cataract Extraction (ECCE) is a critical choice to prevent complications such as posterior capsular rupture and vitreous loss. The ideal irrigating fluid should have a low viscosity, be non-toxic, and not cause chemical burns to the ocular tissues.

**Why the Correct Answer is Right**
The correct answer is **B. Balanced Salt Solution (BSS)**. BSS is a physiologically balanced solution that closely mimics the composition of the aqueous humor. It contains sodium, potassium, calcium, magnesium, and chloride ions in a specific ratio that maintains the osmotic balance and pH of the ocular tissues. The use of BSS during ECCE helps to prevent posterior capsule rupture by maintaining a stable anterior chamber pressure and reducing the risk of vitreous loss.

**Why Each Wrong Option is Incorrect**
**Option A:** **Ringer's Lactate** is not suitable for intraocular use as it has a high pH and can cause chemical burns to the ocular tissues.
**Option C:** **Normal Saline** is hypotonic and can cause an influx of water into the ocular tissues, leading to swelling and potential complications.

**Clinical Pearl / High-Yield Fact**
It is essential to note that the use of BSS during ECCE is not only limited to the irrigating fluid but also as a tamponade agent to help maintain the anterior chamber pressure and prevent posterior capsule rupture.

**Correct Answer: B. Balanced Salt Solution (BSS)**