What is a plateau and how can one form?

A plateau is generally an elevated highland area, which ranges upto thousands of kilometers. They have a relatively flat terrain and they appear like a table-shape, and is formed due to the erosion of the sides as well as on the surface. For example, the Deccan plateau and the Shillong plateau.

These plateaus are formed in various ways, such as-

primary succession begins with a bare rock and ends with a forest secondary succession begins after a natural disaster where there is a temporary setback after a forest fire or local destruction, but the surrounding area can fill in

i think its both a and b