Same group of ancestors have formed mammals adapted to running, flying and swimming. This proves

In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges and opens environmental niches. Thus, option D is correct.
Adaptive convergence is a form of evolution in which two unrelated (or distantly related) species evolve very similar forms due to similar selective pressures.  Thus, option C is wrong.
Genetic drift or allelic drift is the change in the frequency of a gene variant (allele) in a population due to random sampling. Thus, option B is wrong.
Speciation is the evolutionary process by which new biological species arise. Thus, option A is wrong.