"Static Boost" is the manifold pressure indicated on the boost pressure gauge when:

The correct answer refers to "Static Boost" as the manifold pressure indicated when the engine is stopped. This is based on the fact that "Static Boost" measures the pressure in the manifold without the influence of engine dynamics and airflow that occur when the engine is running. When the engine is stopped, the manifold pressure gauge reflects the boost pressure generated by the supercharger or turbocharger that remains in the system, allowing for a clear indication of the boost potential without the complications of engine load and rpm.

When the engine is running, factors such as air intake, fuel combustion, and the engine's speed affect the manifold pressure reading, making it change from the static value. Therefore, other options that pertain to engine operation at idle speed, rated power, or specific gauge position do not depict the true static condition meant by the term "Static Boost."