Final answer:
Option 4: Visibility, Vigilance, Training are the three key elements of a good patrol.
Step-by-step explanation:
Option 4: Visibility, Vigilance, Training are the three key elements of a good patrol. Visibility ensures that the patrol is easily detectable, Vigilance refers to the alertness and attentiveness of the patrol members, and Training ensures that the patrol members have the necessary skills and knowledge to carry out their duties effectively.