The most straightforward answer is D - using an individual's genetic information to decide who can be covered for health insurance.
This is unethical because people have no say over which genes they were born with. Furthermore, applying this logic would mean that we are proponents of genetic determinism. While genes have an impact, a person can still choose to apply different protocols in his life that help him combat his chances for certain diseases.
It could be also considered unethical if people themselves would be provided guidance based on the genetic information collected, without any proper medical consultation beforehand.
