It is D,Copernicus.when he first proposed the idea everyone thought he was nuts and that it was not plausible.even though his theory wasn't so accurate it still helped further scientific research.HE was born February 19,1473 and he published a book about his theory.
300 000 000 m/s in km/s
1000 m = 1km
300 000 000 m/s = 3 * 10⁸ m/s = 3 * 10⁵ *10³ m/s
= 3 * 10⁵ *10³ m/s
= 3 * 10⁵ km/s
Speed = 3 * 10⁵ km/s