Question

Which part of earths surface has the greatest rotational speed

Answer 1

Every point on the surface must have the same rotational speed.
Otherwise some places would rotate away from other places.

If the next block of your city rotated faster than the block that you live on,
then you could sit at home, look out the window, and watch your school
rotate past your house.

The map of the continents on the Earth would change constantly.