What triggered the cyclic model of the origin of the universe?

Question

A: some scientists think that the universe will not keep expanding forever.
B: some scientists began to use telescopes and mathematics to study the universe.
C: some scientists found that the amount of radiation in space is not consistent with an explosion.
D: some scientists argue that the planets do not orbit in circles around the sun.

Answer 1

C: some scientists found that the amount of radiation in space is not consistent with an explosion.