According to the nebular theory, how did the Oort cloud form? a. It consists of objects that fragmented from the protosun during a catastrophic collision early in the formation of the solar system. b. It is made of planetesimals formed in the outer solar system that were flung into distant orbits by encounters with the jovian planets. c. It is made of planetesimals between the orbits of Mars and Jupiter that never formed into a planet. d. It is material left over from the interstellar cloud that never contracted with the rest of the gases to form the solar nebula.