Concept:Block mountains, also called fault mountains, form when large sections of the Earth’s crust are broken and displaced vertically along faults due to tensile forces. They have steep slopes and a flat top.Explanation:The given options represent different mountain types. The Himalayas are young fold mountains, formed by plate collision. The Appalachians and the Urals are old fold mountains, heavily eroded over time. The Vosges mountain, located in the Rhine Valley, is a classic example of a block mountain. It was created by faulting and vertical displacement of the crust. Therefore, among the options, only the Vosges is a block mountain.Answer:D. Vosges