A person manning a fire hose under pressure with an all-purpose nozzle attached should be aware that the nozzle is most difficult to control when the handle position is changed from __________.

Correct Answer: Option D — shut to solid stream

Transitioning from a shut position to a solid stream creates a sudden, massive reaction force due to the rapid acceleration of water mass. This instantaneous change in momentum can cause the nozzle to whip or jerk, making it the most physically demanding and difficult maneuver for a firefighter to control.