Which of the following is/are Incorrect statements about the observation/work of Darwin and Hugo de Vries?

Options

A. Charles Robert Darwin clearly and convincingly set forth the concept of natural selection as the mechanism of evolution, de Vries gave mutation theory
B. Darwin emphasised the adaptive nature of variation, de Vries stressed on its randomness
C. According to Hugo de Vries variations are small and directional, but Darwinian variations are random and directionless
D. Evolution for Darwin was gradual while de Vries believed mutation caused speciation and hence called it saltation