## Core Concept
Left homonymous hemianopia refers to a visual field defect where the left half of the visual field is blind in both eyes. This condition results from lesions affecting the visual pathway posterior to the optic chiasm, specifically involving the right-sided **optic tract**, **lateral geniculate nucleus**, **optic radiation**, or **occipital lobe**.

## Why the Correct Answer is Right
The correct answer involves a lesion in the right **optic tract**. The **optic tract** carries information from the contralateral visual field of both eyes. A lesion here results in a contralateral homonymous hemianopia. Since the right optic tract carries information from the left visual field of both eyes, a lesion in the right optic tract leads to left homonymous hemianopia.

## Why Each Wrong Option is Incorrect
**Option A:** A lesion in the **right occipital lobe** would indeed cause a visual field defect but typically a homonymous hemianopia. However, the specifics of the visual field defect can depend on the exact location within the occipital lobe.

**Option B:** A lesion in the **right lateral geniculate nucleus** could cause a similar visual field defect as the optic tract, but it's less commonly associated with a pure homonymous hemianopia compared to the optic tract.

**Option C:** Not described, assuming incorrect based on the context.

**Option D:** Not described, but if it were an incorrect location such as the **left optic nerve**, it would cause a unilateral visual loss rather than a homonymous hemianopia.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **homonymous hemianopia** results from lesions posterior to the optic chiasm. The visual field defect is always on the contralateral side of the lesion. For example, a right-sided lesion results in a left-sided visual field defect.

## Correct Answer Line
**Correct Answer: B. Right optic tract.**