Which of the following best summarizes the author's argument?
A
The author explained how evolution had resulted in diversification and changes in living things, the origins of which could be identified.
B
The author explains how evolution has resulted in diversification and changes in living things, the origins of which can be identified.
C
The author is explaining how evolution is resulting in diversification and changes in living things, the origins of which can be identified.
D
The author had explained how evolution had resulted in diversification and changes in living things, the origins of which could have been identified.