What are Arturo Montero and Guillermo de Anda NOT investigating in the cenote? (Text 1A)

A、whether the ancient Maya had depleted the cenote’s water from overuse;

B、whether the ancient Maya went there to give thanks and offer sacrifices;

C、whether the ancient Maya used the cenote as a sundial and timekeeper;

D、whether ancient Maya priests used the cenote to correct their measurements of the sun’s angle when it reached the zenith