Two Siblings Can Grow Up in Identical Environments and as Adults

Two siblings can grow up in identical environments and as adults, one develops a psychological disorder and the other does not. Psychologists have taken biological, psychological, and environmental factors and explored how these factors relate to each other in order to explain the above situation. This is called the:

A) reliably-valid model
B) predisposition-dysfunction model
C) vulnerability-stress model
D) psychodynamic model