Concept:A block mountain is created when large sections of the Earth’s crust are displaced along faults.Explanation:The Earth’s crust can break due to strong tectonic forces.This breaking is called faulting.When faulting occurs, some blocks of land are pushed upward while others sink down.The raised blocks form block mountains.Other options like vulcanicity, fissure, and differential erosion do not directly create block mountains.Answer:D. faulting