Einstein's theory of general relativity describes how space and time are connected. What makes this idea a theory?

a. Einstein was a known genius

b. It was supported by observations and evidence

c. Two or more people debated it

d. It was about an unknown hypothesis

B. A hypothesis is just an idea. And can become a Theory if there is some evidence. However a Theory is not a law, but an idea with supportive evidence

b. It was supported by observations and evidence

Explanation:

An idea becomes a theory when it is supported by observations and evidence. The idea is tested multiple times and if it gives similar results, then it is accepted and becomes a theory.

Einstein's general theory of relativity became theory when it was supported by various observations and evidence.