Historian: Fifteenth-century advances in mapmaking contributed to the rise of modern nation-states. In medieval Europe (from the fifth to the fifteenth century), sovereignty centered in cities and towns and radiated outward, with boundaries often ambiguously defined. The conceptual shift toward the modern state began in the late fifteenth century, when mapmakers learned to reflect geography accurately by basing maps on latitude-longitude grids. By the midseventeenth century, nearly all maps showed boundary lines. Which of the following would, if true, most strengthen the historian's reasoning? ['During the fifteenth century in Europe, mapmakers simplified the borders of sovereignty by drawing clear lines of demarcation between political powers.', 'Seventeenth-century treatises and other sources of political authority describe areas of sovereignty rather than illustrate them using maps.', 'Borders did not become codified in Europe until certain treaties were signed in the early nineteenth century.', 'During the medieval period, various authorities in Europe claimed power over collections of cities and towns, not contiguous territories.']