The correct answer to the question is option 3 - Big Bang theory. The Big Bang theory is the prevailing scientific explanation for the origin of the universe. According to this theory, the universe started as an extremely hot and dense point around 13.8 billion years ago and has been expanding since then.

Option 1 - Nebular Hypothesis, is a different scientific explanation that focuses on the formation of our solar system. It describes the formation of the Sun and planets from a rotating disk of gas and dust.

Option 2 - Binary theory, is not a widely recognized hypothesis or theory explaining the origin of the universe. It may have been included as a distractor or a possible misconception.

Option 4 - Planetesimal hypothesis, is another theory related to the formation of our solar system. It suggests that small bodies called planetesimals collided and gradually formed larger planets.

In conclusion, while options 1, 2, and 4 are related to the formation of our solar system, the Big Bang theory is the leading explanation for the origin of the entire universe.