The first one is correct. "It is like" the best decision you can ever make.
Saying it that way, is the same as saying that it would be the best decision that you can ever make, but adding more to it. Almost as if soeaking to someone who is overdramatic, and constantly say the word like.
I hope this helps
It is figurative because it is like a figure of speech
I think it is D.
But A could possibly be the answer but D technically includes A.
