**Core Concept**
Deterministic effects of radiation are a type of radiation injury that occurs when the dose of radiation received is high enough to cause predictable damage to specific tissues or organs, resulting in a specific severity of response. This type of effect is typically seen at doses above 100 cGy (cubic centimeters of tissue per 100 rad) and is often characterized by a clear dose-response relationship.

**Why the Correct Answer is Right**
The severity of response in deterministic effects is directly related to the dose of radiation received, with higher doses resulting in more severe tissue damage. This is because deterministic effects involve the direct killing of cells or damage to specific tissues, such as the gastrointestinal tract or the central nervous system, which can lead to predictable outcomes like nausea, diarrhea, or even death. The radiation-induced damage to these tissues is thought to be due to the ionization of DNA, leading to mutations or cell death.

**Why Each Wrong Option is Incorrect**
**Option A:** Non-stochastic effects, such as radiation-induced cataracts, are also deterministic but are characterized by a threshold dose below which no effect is seen.
**Option B:** Stochastic effects, such as cancer or genetic mutations, are not deterministic because the likelihood of these effects increases with dose but the severity of the response is not predictable.
**Option C:** The severity of response in deterministic effects is not related to the individual's sensitivity to radiation, unlike stochastic effects.

**Clinical Pearl / High-Yield Fact**
Remember the "4 Rs" of radiation injury: **Reversibility** (deterministic effects can be reversible with time), **Relevance** (deterministic effects are related to the dose and type of radiation), **Responsiveness** (individuals may respond differently to radiation), and **Risk** (deterministic effects are predictable and related to dose).

**Correct Answer:** D.