**Core Concept**
Cone Beam Radiography is a type of computed tomography (CT) imaging that uses a cone-shaped X-ray beam to capture a 3D image of the body. The raw digital data for reconstruction is obtained through a process called cone beam computed tomography (CBCT).

**Why the Correct Answer is Right**
The correct answer is that the raw digital data for reconstruction is obtained from the **detector array**. The detector array is a critical component of the CBCT system, consisting of a large number of individual detectors that convert the X-ray photons into electrical signals. These signals are then processed and reconstructed into a 3D image using advanced algorithms. The detector array is typically made up of a large number of photodiodes or other types of sensors that are arranged in a specific pattern to capture the X-ray data.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the **X-ray source** is responsible for producing the X-ray beam, but it is not the component that captures the raw digital data.
**Option B:** This option is incorrect because the **reconstruction software** is used to process and reconstruct the raw data into a 3D image, but it is not the component that captures the raw data.
**Option D:** This option is incorrect because the **image processing unit** is used to display and manipulate the reconstructed image, but it is not the component that captures the raw data.

**Clinical Pearl / High-Yield Fact**
A key advantage of Cone Beam Radiography is its ability to capture high-resolution 3D images with a single rotation of the X-ray beam, reducing radiation exposure and increasing diagnostic accuracy.

**Correct Answer:** D. Image processing unit