Final answer:
The unsupported conclusion is the idea that the author views STEM instruction as wasteful. Instead, the article advocates for integrating social studies with other subjects to create well-informed global citizens (Option D).
Step-by-step explanation:
The conclusion not supported by the article is that the author thinks STEM instruction is a waste of children's time. The article highlights the importance of fostering a general awareness of foreign cultures, geography, and history, as well as the urgency to support children's learning in these areas. It encourages parents to utilize resources like globes, world maps, children's atlases, and nonfiction books to deepen their children’s understanding of the world.
Furthermore, it emphasizes how the study of world history and geography is essential in forming mindful world citizens, prepared for modern life and global workplaces.
Thus, the correct option is D.