What is one cause of long-lasting climate change? A. Volcanic activity

B. Earth’s elliptical orbit

C. Earth’s rotation

D. The Sun’s elliptical orbit

A. Volcanic activity

You can approach this question in two ways:

One:
when volcanos erupt (called volcanic activity), they will expel enormous amounts of soot, rock, smoke, and other materials into the air. This material, if light enough, floats around in the atmosphere and can block the sun. The CO2 and other greenhouse gases produced can also contribute to global warming

Two:
Notice how volcanic activity is something that happens randomly and ‘rarely’. However, answers B, C, and D happen all the time. Earth is always spinning, it’s also always rotating around the sun. The sun also never stops moving: its main motion is from revolving around the Milky Way. Thus, it makes sense to choose the one random, rare event. This is because we only see long-lasting climate change occasionally, and thus it can’t be something ordinary like earths rotation.

It's speed of rotation.