The correct connection the author draws between Earth Day and corporations is:
C. Companies eventually started using Earth Day to show how green they are.
Explanation:
- Initially, Earth Day was a grassroots environmental movement focused on raising consciousness about environmental issues.
- Corporations did not immediately support Earth Day; instead, over time, many companies began to use the event as an opportunity to showcase their environmental responsibility and green initiatives.
- This shift often involves marketing efforts highlighting sustainability to improve public image, rather than early direct cooperation with the original protestors or forcing governmental recognition.
- Therefore, the author implies that companies eventually co-opted Earth Day for promotional purposes, rather than being original backers or consistent opponents.