How many primary defensive zones exist in the PLA defensive model?

• A. Five Defensive Zones
• B. Four Defensive Zones
• C. Six Defensive Zones
• D. Three Defensive Zones

Answer: (A)

The concept being tested is defense-in-depth organized into distinct layers. In this PLA model, defense is structured into five primary zones that extend from the forward area back into depth. This five-zone arrangement gives the defender multiple, overlapping lines of resistance, creating time and space for maneuver, denying the attacker quick breakthroughs, and providing opportunities for timely counterattacks with reserves. Each zone has a intended role—contesting the front, absorbing momentum, trading space for time, exploiting breakthroughs, and reinforcing from the rear—and together they form a flexible, layered defense.

Why five is the best fit here is that it establishes a complete depth profile without overcomplicating command and control or leaving a gap in coverage. Fewer than five could compress or blur critical functions, reducing the ability to delay and degrade an attacker. More than five would add unnecessary complexity for planning, coordination, and resupply, potentially slowing decisive actions.