Choose the best description, definition for Uniformitarianism. Please help im failing badly

The correct answer is b. The principle of Uniformitarianism is based on the idea that Earth´s physical landscape is the result of processes and forces that have happened uniformly since the earth formed.  

Explanation:

Stated by the geologist James Hutton, this principle says basically that all the geological processes that currently occur had also occurred in the past. Based on this principle, many events might be explained, and not only geological events, but also biological events.

The Uniformitarianism or Uniformism principle states that all the processes that have occurred during the whole Earth history, have been uniform (that is why this principle is named Uniformitarianism) and similar to the current processes.

This principle is very important nowadays, but knowing that not all processes are completely uniform, they have been changing heir intensity and rhythm. Besides, there is a very important factor that is not repeatable, living organisms, that have been lineally changing throughout history.

what following? you said which of the following. but there is no be more specific.