Answer:
A. modern organisms closely resembling fossils
Step-by-step explanation:
Fossils are defined as the preserved remains or traces of living organisms from past.
Fossils are considered as an evidence for evolution because they represent the existence of life on earth and shows the difference between the life in past that life on earth today. With the help of fossil, it is easy to determine the age of fossils which further help to determine that how modern organisms have evolved from the past.
Hence, the correct answer is "A. modern organisms closely resembling fossils".