Which of the following is a principle of crime prevention through environmental design (CPTED)?

Crime Prevention Through Environmental Design (CPTED) is a proactive design philosophy that uses environmental elements to reduce crime opportunities. One of its core principles is natural surveillance, which involves designing spaces so that legitimate users can easily observe their surroundings. This increases perceived risk for offenders and discourages criminal activity.

A (Balanced systems), B (Protection in depth), and D (Layered defense) are principles used in security system design but not specific to CPTED.