According to our theory of solar system formation, why do all the planets orbit the Sun in the same direction and in nearly the same plane?
A. The original solar nebula happened to be disk-shaped by chance.
B. Any planets that once orbited in the opposite direction or a different plane were ejected from the solar system.
C. The laws of conservation of energy and conservation of angular momentum ensure that any rotating, collapsing cloud will end up as a spinning disk.
D. The Sun formed first, and as it grew in size it spread into a disk, rather like the way a ball of dough can be flattened into a pizza by spinning it.
E. Luck explains it, as we would expect that most other solar systems would not have all their planets orbiting in such a pattern.