The correct option is D.
The model developed by Ptolemy has a lot of inconsistency and during the middle age additional explanation was offered for the claims made by the model. The model was very complicated because it was based on erroneous assumptions.
Copernicus model was simpler and some of his claims were correct.<span />
I don't quite know what you're asking so I'll just go on a rant :) Wegener created and supported the continental drift theory, which stated that all of the continents once formed a super continent called Pangea. No one at the time believed in the theory though so he spent the rest of his life trying to find evidence to prove it. However, after he died scientists began to find information that supported his theory. When scientists began to study Earth's surface and the layers below, the theory of the tectonic plates was formed. This theory stated that Earth's crust, the lithosphere, was divided into twelve moving plates. This theory did in fact prove that Wegener's theory was correct. Another theory that proved Wegener's theory to be true was the process of Sea Floor Spreading. This theory stated that at divergent plate boundaries, new ocean floor was being created and the old was being pushed away from the boundary, the old sea floor would then be pushed to deep sea trenches created by convergent plate boundaries and essentially recycled back into the Earth. I hope this helped, sorry it is so long :)
The centripetal acceleration is given by

where v is the tangential speed and r the radius of the circular orbit.
For the car in this problem,

and r=40 m, so we can re-arrange the previous equation to find the velocity of the car:
<span>C. The filings will be clustered more densely where the field is weakest.</span>