What are the main functions of a physical protection system (PPS)?

What are the main functions of a physical protection system (PPS)?
A . The primary functions are detection, delay, and record. Deterrence is a secondary function.
B. The primary functions are direct, delay, and response. Deterrence is a secondary function.
C. The primary functions are determine, delay, and response. Deterrence is a secondary function.
D. The primary functions are detection, delay, and response. Deterrence is a secondary function.

Answer: D