Which of the following factors makes an epidemiologic study less likely to be valid?

Jack has cancer which is inoperable. there is a treatment that can prolong his life for up to 18 months but which cannot provide a cure. the procedure is very expensive and although he does have medical insurance, the insurance company is dragging its feet and will not provide authorization. their thinking is that if they can delay a decision until jack dies they can save a significant amount of money. which ethical rule drawn from the law are they most specifically violating?