The correct answer is - C. Weathering, erosion, and uplift occur at the same rates now as they did in the past.
The concept of the uniformitarianism is that everything has been occurring at the same rate throughout the whole geological time scale, and that is how it continues in the present. So pretty much, everything changes at the same rate all of the time.
In this case, according to the uniformitarianism, the process of weathering, erosion, and uplift are occurring at the same rates in the present, as they have been occurring in throughout the whole past.
This concept is not widely accepted, and there's lot of proofs against it.