What Does "Diffusion of Benefits" Refer To

What does "diffusion of benefits" refer to?

A) a crime reduction program that produces only a short-term effect on the crime rate until criminals adjust to the new conditions
B) preventing innocent bystanders from becoming original or intended victims
C) the shift of crime to another area after the implementation of a crime prevention program
D) prevention efforts directed at one type of crime that cause the unintended prevention of another type of crime