The idea of the sun in the middle of the solar system, with planets orbiting around it originated with whom?

a) erasmus

b) kepler

c) newton

d) copernicus

i'm pretty sure it's copernicus, but does anybody else know?

The correct answer is Copernicus. 

Nicolaus Copernicus proposed this idea in his book that Sun is in the middle of the solar system and planets are revolving around the sun in perfect circles. The title of his book was "Revolution of the Celestial Spheres" and was published in 1543. Prior to his book, the general belief was that earth is the center of the solar system. Later Kepler also supported the idea of Copernicus but Kepler said the orbits are elliptical. So the answer to this question is Copernicus as he was the first one to give this concept through his book.