What is this near the bottom right corner (pic in details)?
It just means that people can copy your answer as long as they follow the guidelines set out by the license.
Socratic is a place for learning, so when someone writes an answer, they do so to teach students.
However, that answer it still theirs, and so it still holds some license. These can be found in the other answer above.
That's Socratic's license.
All the content posted on Socratic is licensed under Creative Commons, CC.
As you can see, Socratic uses a Creative Commons-Attribution-NonCommercial-ShareAlike license, which you'll find listed under the impact map on every question page.
This implies that content posted here can only be used with attribution, for non-commercial purposes, and using the same license.
So keep in mind that CC licenses are copyright licenses. This means that what you post on Socratic cannot be used under other conditions than the ones specified by the license.