A Serial Killer Has Been Dumping His Victims' Bodies Along

A serial killer has been dumping his victims' bodies along the highways in several states. Using computer programs for geographic profiling, a crime analyst is close to pinpointing a buffer zone, which is an area where the perpetrator:

A) is less likely to commit crimes.
B) is more likely to commit crimes.
C) did commit crimes that have not been discovered yet.
D) tries to return to, in order to clean up the crime scene.