**Core Concept**
Silver halides, specifically silver bromide (AgBr), silver chloride (AgCl), and silver iodide (AgI), are commonly used in radiographic imaging due to their high sensitivity to light. Among these, silver bromide is the most widely used due to its optimal balance of sensitivity and stability.

**Why the Correct Answer is Right**
Silver bromide is the primary light-sensitive crystal present in X-ray film. When X-rays pass through the film, they ionize the silver bromide, converting it into silver ions and bromide ions. This process creates a latent image that is then developed into a visible image through a series of chemical reactions. The high sensitivity of silver bromide to X-rays makes it an ideal choice for radiographic imaging.

**Why Each Wrong Option is Incorrect**
* **Option A:** Silver chloride (AgCl) is less sensitive to X-rays compared to silver bromide and is not as commonly used in radiographic imaging.
* **Option B:** Silver iodide (AgI) is highly sensitive to light but has a lower sensitivity to X-rays, making it less suitable for radiographic imaging.
* **Option D:** There is no widely used crystal with this designation in radiographic imaging.

**Clinical Pearl / High-Yield Fact**
In radiographic imaging, the choice of silver halide crystal is critical in determining the sensitivity and quality of the final image. Silver bromide is the most commonly used crystal due to its optimal balance of sensitivity and stability.

**Correct Answer:** C. Silver bromide