Final answer:
The term for men who relied on firearms, especially during American westward expansion, is 'Frontiersmen'. Gunsmiths make and repair guns, whereas sharpshooters and marksmen are terms for skilled shooters. Therefore correct option is D
Step-by-step explanation:
The common term for men who made their way with guns, particularly in the context of American history and frontier expansion, is D) Frontiersmen. These individuals were often pioneers who carried firearms for hunting and protection as they moved into and settled the American West. They were not necessarily gunsmiths, who are craftsmen that make and repair guns, nor were they exclusively sharpshooters or marksmen, terms that refer to individuals with precise shooting skills. The history of firearms is deeply intertwined with the expansion of colonial empires and had significant implications for both the settlers and the native populations they encountered.