While in the Yucatan Peninsula, a tourist could visit underground sinkholes filled with water that the Mayans called _____.

The Yucatan Peninsula has natural sinkholes that expose groundwater, forming pools or caves filled with water. The Maya called these cenotes, so choice C is correct. Castillos are structures, caracoles are spiral shapes or shells, and the Toltecs were a people, not the name for these sinkholes.

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