The correct answer is A) has its main deck plating under tensile stress. Hogging is a condition where the ends of a vessel are bent upwards, causing the main deck plating to be under tensile stress. This is due to the weight of the vessel's hull and cargo being concentrated in the middle, which puts the main deck under tension. The bottom plating, on the other hand, would be under compressive stress in a hogging condition. The other options are incorrect because: B) the main deck would be under tensile stress, not compressive stress; C) the bottom plating would not be under ductile stress, but rather compressive stress; and D) the bottom plating would be under compressive stress, not tensile stress.