题目选项分析

Unlike other Mayan cities, Cancun seems to have used its strategic position at the foot of the highlands, a source of jade, obsidian, and other valuable commodities, to become a commercial power throughout the lowlands.

Unlike other Mayan cities, Cancun's commercial power throughout the lowlands seems to be from using its strategic position at the foot of the highlands, which were a source of jade, obsidian, and other valuable commodities.