If a fire is detected in a main propulsion gas turbine enclosure, which of the following would occur prior to automatic release of the fire extinguishing agent?

Correct Answer: Option B — If open, bleed air valves would be closed.

To ensure the effectiveness of the fire extinguishing agent, the enclosure must be sealed. Closing bleed air valves prevents the introduction of high-pressure air into the enclosure, which would otherwise feed the fire and dilute the concentration of the extinguishing agent, rendering the suppression system ineffective.