GIVING BRAINLIEST, PLS Help ASAP What is an example of historical causation?

A. European explorers arriving in the Americas brought new diseases with them, which would spread to indigenous people, and caused many deaths.

B. the changing weather between seasons caused many bird species to migrate south for the winter and lay their eggs in warmer climates.

C. People who left too early or too late on the Oregon Trail often died because of harsh weather conditions, lack of food, and diseases.

D. Rainbows are caused by sunlight in specific atmospheric conditions.