Which of the following statements about Davis’ Cycle of Erosion are correct?

a) Davis argued that landforms evolve through youth, maturity, and old age, analogous to a living being’s life cycle.

b) The youthful stage is characterized by lateral erosion dominating over vertical erosion.

c) The concept of "peneplain" refers to a nearly flat landform with isolated residual hills called monadnocks.

d) Davis assumed that upliftment occurs rapidly, followed by a prolonged period of stability during which denudation processes act.