Inhabitants of the country Orctania suffer from a much lower incidence of cancer than the inhabitants of other countries, for reasons that are generally theorized to be environmental and behavioral--the pollution-free air, stress-free and drug-free living, healthy dietary practices, and active lifestyle. Nevertheless, people from other countries who take up residence in Orctania and attempt to follow the practices of the inhabitants still have a radically higher incidence of cancer than do native Octanians.
Which of the following does NOThelp to explain the higher incidence rate of cancer in non-native Orctanians?
【选项】
It has not been established which one of several possible factors, or combination of these factors, is truly responsible for the low incidence of cancer in native Orctanians.
选项是否正确？