According to the big bang theory, matter clumped into stars because of a) the expansion of the universe b) the force of fusion c) the force of gravity d) the extreme speed that particles were traveling

the expansion of the universe is the right answer, if you read the right article about the big bang theory you can find out that the expansion of the universe is why.

for example, no new evidence will demonstrate that the earth does not orbit around the sun (heliocentric theory), or that living things are not made of cells (cell theory), that matter is not composed of atoms, or that the surface of the earth is not divided into solid plates that have moved over geological timescales .

characteristics of hydrocarbons