Fixed carbon dioxide extinguishing systems, for machinery spaces that are normally manned, are actuated by one control to open the stop valve in the line leading to the space, and:

Answer & Explanation

The correct answer is Option B: two separate controls to release the CO2.

For normally manned machinery spaces protected by a CO2 system with a stop valve, a two-control operation is required. One control initiates the process (e.g., opening the stop valve), and a second control actually releases the CO2.