Which of the following relationships is considered prohibited under laws concerning incest?

The relationship between a parent and child is considered prohibited under laws concerning incest due to the inherent nature of the familial bond and the expectations of care and protection that must exist between parents and their children. Incest laws are designed to prevent sexual relations and marriages between close relatives, primarily to protect the family structure and to avoid the potential negative consequences that can arise from such relationships, including genetic issues in offspring. The legal definitions of incest generally encompass direct blood relations, and a parent-child relationship falls squarely within that category.

The other relationships listed—friends from college, neighbors, and co-workers—do not share familial ties that would invoke incest laws, thus they do not fall under the prohibitions outlined in such laws.