Identify the correct statements with reference to Geomorphic Cycles of Davis and Penck.

A. Davis considered the cycle of erosion of fluvial process as the 'normal cycle of erosion'.

B. Davis used the concept of 'base level' proposed by Gilbert and concept of 'graded streams' propounded by Powell and applied 'evolutionary paradigm'.

C. In the second sub-phase of the phase of uniform development of landscape of Penck model absolute height increases and relative relief also increases at the same rate.

D. Davis applied the concept of slope decline.

Choose the correct answer from the options given below: