**Core Concept**
Edmund Locard was a French forensic scientist who laid the foundation for the field of forensic science. He is best known for his exchange principle, which states that every contact between two objects will result in an exchange of materials.

**Why the Correct Answer is Right**
Locard's exchange principle is a fundamental concept in forensic science, suggesting that whenever two objects come into contact, they will exchange materials such as hair, fibers, dust, or even fingerprints. This principle is the basis for many forensic techniques, including fingerprint analysis, hair comparison, and trace evidence analysis. The exchange of materials can occur through various means, including touching, handling, or even airborne transmission.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because Locard's exchange principle is not related to the concept of "crime scene reconstruction."
* **Option B:** This option is incorrect because Locard's exchange principle is not specifically related to the analysis of DNA evidence.
* **Option C:** This option is incorrect because Locard's exchange principle is not a theory related to the study of human behavior or psychology.

**Clinical Pearl / High-Yield Fact**
A key aspect of Locard's exchange principle is that it highlights the importance of trace evidence in forensic science. Trace evidence can be incredibly small, but it can still provide valuable information about the events surrounding a crime.

**Correct Answer:** D. His exchange principle.