Instruction: What is the most likely solution to fermi's paradox

Response: This is highly debatable topic and there are several solutions to the Fermi's paradox.However the great filter seems to be the one which has high probabilities than other. in the Great Filter scenario, something occurs to civilization at some point of their lifetime that cause termination and extinction. it is not clear so far what that event could be, and whether it is man-made or form outside.