Uranium is mined in Niger to produce electricity. The residents of Niger are concerned because uranium mining produces cancer-causing radioactive wastes that enter the groundwater they drink. The table below shows the number of cancer patients in the Niger mining community between 1958 and 1974:

Year Fatalities
1958 9
1962 10
1966 10
1970 50
1974 67

Based on the table, which of these is the most likely year when uranium mining was first done in Niger?

I did the test and picked answer C, but it was marked wrong. Is this actually answer correct?