Which Idea Has Been Borne Out by Actual Astronomical Observations

Which idea has been borne out by actual astronomical observations over the past few centuries?

A) The probability of life existing elsewhere in the universe, even elsewhere in our own solar system, is extremely great.
B) Earth appears to occupy a unique position in the universe, unrepeated anywhere, since the Sun is unique in properties and position in a remarkable galaxy.
C) All the observational evidence so far suggests that conditions for the evolution of life exist only on Earth in its position near the Sun.
D) The Sun is an unremarkable star in a commonplace galaxy, and many similar stars exist in the universe around which life might evolve on planets.