Willys-Overland produced 361,339 of its ______ vehicle for the U.S. government from 1942-1945.

The correct answer is MB, as Willys-Overland produced the MB model during World War II specifically for the U.S. military. This vehicle, commonly referred to simply as the "Jeep," became an iconic symbol of the American armed forces during the war and was pivotal in various military operations. The production number of 361,339 reflects the high demand and utility of the MB in a wartime context, showcasing its ruggedness and versatility that made it a favored choice for the military.

Other choices, such as the Jeepster, Willys Wagon, and Gladiator, do not relate to the military production during that period. The Jeepster was a civilian vehicle that came about after the war, the Willys Wagon was produced later as part of a different category of automobiles, and the Gladiator was introduced in the late 1960s. None of these models were involved in the wartime efforts that prompted the high production numbers of the MB.