Correct Response: A. Long-period comets and many other types of comets are believed to have originated in the Oort cloud. The Oort cloud is outside the orbits of the planets and extends to the solar system's outer boundary where the Sun's gravitational influence is very weak. The region contains mostly icy planetesimals and at its outer edge the orbits of these objects can be perturbed by passing stars, occasionally causing them to travel toward the inner solar system. New stars would not form in this region (B) because of the Sun's proximity and the lack of sufficient dust and gas. The asteroid belt (C) is in a different region of the solar system than the Oort cloud. A supernova covers an enormous area and would have obliterated the solar system had it occurred in the region occupied by the Oort cloud (D).
