Answer:
D. Newton’s and Einstein’s ideas are like the word “red” in English or Spanish.
Step-by-step explanation:
When writting a summary for any text, one should be able to distinguish main ideas from less important parts and to include only those essential information.
Now, this article deals with two theories that explain gravity and the circumstances under which each of them works or doesn't work.
So, those are pieces of information that definitely need to find their place in the summary and we see that those claims are stated in answers A. B. and C.
Finally, answer D. is only an example of the way Newton's and Einstein's theory can be compared. It helps readers to better understand the text, but it's not an essential part of the text itself.