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

A、whethertheancientMayahaddepletedthecenote’swaterfromoveruse;
B、whethertheancientMayawenttheretogivethanksandoffersacrifices;
C、whethertheancientMayausedthecenoteasasundialandtimekeeper;
D、whetherancientMayapriestsusedthecenotetocorrecttheirmeasurementsofthesun’sanglewhenitreachedthezenith