Answer
C. DNA
Step-by-step explanation
During Darwins time, he used types of evidence to prove his theory, this evidence included the use of fossils and similarities between related living organisms (comparable anatomy), were used by Darwin to develop his theory of natural selection, and are still used today. However, others such as DNA testing, were not available in Darwin's time, but are used by scientists today to learn more about evolution. Therefore the answer is C - DNA.