A doctor tests a new drug prescribed to 140 leukemia patients. After 6 years, 84 of them are still alive. What proportion of all leukemia patients will still be alive after 6 years of treatment with this level of drug, with 95% certainty?

O 53.8%; 66.2%) O 50.3%: 69.7%) O 52.4%; 67.6%) O (51.2%; 68.8%) O 51.9%; 68.1%)