Final answer:
Option D. The nurse should target families with two teenagers, corresponding with the "Launching Family" stage of the family lifecycle where the last child is leaving or has left home.
Step-by-step explanation:
The nurse preparing teaching materials on preventive health for families in Stage V of the family lifecycle should be targeting families with two teenagers. This is consistent with what is often referred to as the "Launching Family" stage, in which the last child is getting ready to leave home or has recently left. At this stage, the family adapts to the empty nest and the shifting parental roles.
The focus of preventive health teaching should thus include topics relevant to parents and teenagers during this transitional period. The nurse should target families with two teenagers, corresponding with the "Launching Family" stage of the family lifecycle where the last child is leaving or has left home.