Read the following passage: "The monarch butterfly undertakes an incredible annual migration. Spanning thousands of miles, these delicate creatures travel from Canada and the U.S. to warmer climates in Mexico and California for the winter. This journey often takes multiple generations to complete, with each generation playing a crucial role in reaching the final destination." What is the main idea of this passage?
✓ Correct Answer: Option B
The passage primarily discusses the long, multi-generational migration of the monarch butterfly, making this the central theme.