c. The current changes are happening much faster than past changes.
Explanation:
This is correct because the earth's atmosphere is warming at an exceedingly high rate. This is due to the rise in amounts of carbon dioxide in the atmosphere among other factors. If the current trends were a representation of Earth's natural climate cycle then they would not be as high as they are now.
Have a great day. I assure you this is the correct answer. Let me know if you have any questions on this topic.
