Which explanation of the solar system best fits the observations of the planets and how they orbit the sun?
a. the gravity of a large, massive star passing the sun ripped off blobs of material from it that formed the planets
b. the planets formed at the center of a collapsing spinning cloud of gas and dust
c. the sun and planets formed from a collapsing spinning cloud of gas and dust.
d. a comet hit the sun and sent off fragments the became the planets.
i'm pretty sure it's c?

You're right, Answer C

The dust and gas accumulate to form a solar nebula, which later on creates the star and the planets.

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.