**Core Concept**
Radiation-induced cataract is a type of cataract that forms due to exposure to ionizing radiation, such as from medical treatments or environmental sources. This condition is characterized by the accumulation of damage to the lens fibers in the eye, leading to the formation of opacities.

**Why the Correct Answer is Right**
The correct answer, **C. Posterior Subcapsular cataract**, is the type of cataract most commonly associated with radiation exposure. This is because ionizing radiation primarily damages the posterior subcapsular region of the lens, leading to the formation of opacities in this area. The posterior subcapsular region is particularly susceptible to radiation damage due to its high metabolic activity and rapid cell division. As a result, radiation-induced cataract typically presents with opacities in the posterior subcapsular region.

**Why Each Wrong Option is Incorrect**
* **Option A:** Shield cataract is not a recognized term in ophthalmology, and it is not associated with radiation exposure.
* **Option B:** Anterior polar cataract is a type of cataract that forms in the anterior (front) part of the lens, and it is not typically associated with radiation exposure.
* **Option D:** Alport syndrome is a genetic disorder that affects the type IV collagen in the body, leading to kidney disease, hearing loss, and eye abnormalities, including cataracts. However, it is not directly related to radiation exposure.

**Clinical Pearl / High-Yield Fact**
Radiation-induced cataract can occur even at relatively low doses of radiation, and it is a significant concern for individuals who have received radiation therapy to the head or neck.

**✓ Correct Answer: C. Posterior Subcapsular cataract**