What is the primary reason why we know that methane from natural gas drilling operations has polluted some water wells in Pennsylvania? Group of answer choicesA. Faults have been mapped that connect the shale formations to the surface, thus allowing a conduit through which methane can travel from the shale to the water wells. B. The carbon isotopic measures of methane from shale formations matches those from water wells and the most contaminated water wells are within a kilometer of the natural gas wells.C. The water wells are all located more than 6km away from the nearest natural gas well.D. All of the above