Answer:
The following statement is one of the way which the author establish the link:
A. The author states that birds are reptiles.
Explanation:
In the passage, the author was able to show various ways about the link between the reptiles and the birds. One of the ways is, the similarities between dinosaurs and birds which he was able to point out in the passage.
To him, the body features of both are similar. Also, he able to show through explanations the different ways which the birds differs from the reptiles. This helps to clarify the two by letting the readers know that, despite the similarities between the birds and reptiles, there are also major differences between them.