trick question

lets say I want to render a texture mapped sphere that is rotating, an image of a rotating planet for example.

Which way is faster ?
a) Rotate the texture mapped sphere.
b) use TexCoord to change where the texture gets mapped and give the impression that the sphere is rotating.

For the 3D pros, same question as above, but with a bumpmapped sphere


In my point of view, I think that the second method is the slowest as u have to add a value to all texture coordinate. And there are two texture coordinate (U and V) by vertex… whereas the first method is only a matrix multiplication.

I’m may be wrong but this is what I think.