The correct answer is C) establish flooding boundaries and prevent further spread of flood water. The reasoning behind this is that when a vessel is damaged and partially flooded, the immediate priority is to contain the flooding and prevent further damage. Establishing flooding boundaries by closing watertight doors, hatches, and vents helps to isolate the flooded areas and stop the water from spreading to other parts of the vessel. This is a critical first step in the damage control process, as it helps to maintain the vessel's overall stability and buoyancy. The other options are not the most appropriate first steps in this situation. Option A) would require additional time and information to assess the vessel's stability, which should be done after the flooding has been contained. Option B) of pumping out the water is not the most effective first step, as the priority is to stop the flooding before attempting to remove the water. Option D) of plugging the hole(s) may be necessary, but should be done after the flooding has been contained and the spread of water has been stopped.