## Core Concept
X-rays are a type of electromagnetic radiation used in medical imaging to visualize internal structures of the body. They work by passing through tissues and being absorbed at different rates, depending on the tissue density. This differential absorption is what allows for the creation of images.

## Why the Correct Answer is Right
The correct answer, although not directly provided, relates to understanding the characteristics and applications of X-rays. Typically, statements about X-rays might involve their ability to penetrate tissues, their use in diagnosing bone fractures, and their potential risks such as causing DNA damage.

## Why Each Wrong Option is Incorrect
Without specific details on options A, B, C, and D, a general approach to evaluating incorrect statements about X-rays:
- **Option A:** If a statement claims X-rays can be used for real-time imaging without mentioning the need for contrast agents or specific technologies like fluoroscopy, it might be incorrect.
- **Option B:** If a statement suggests X-rays have no ionizing effect, it would be incorrect because X-rays do have ionizing radiation, which can potentially damage living tissues.
- **Option C:** If a statement implies X-rays are only used for bone imaging, it would be too narrow, as X-rays are also used for lung, gastrointestinal (with contrast), and other tissue imaging.
- **Option D:** If a statement claims X-rays pose no risk to patients, it would be incorrect due to the potential for radiation-induced harm.

## Clinical Pearl / High-Yield Fact
A crucial point to remember is that while X-rays are invaluable for diagnosis, their use must be justified based on clinical need due to the potential risks associated with ionizing radiation. The principle of keeping doses "as low as reasonably achievable" (ALARA) is key in medical imaging.

## Correct Answer Line
**Correct Answer: D.**