FOR ENGLISH Read this sentence again.

In studying bones of the smaller toes of fossilized skeletons, scientists observed that the thickness of these bones decreased somewhere between 40,000 and 26,000 years ago.

How does the sentence develop the author’s claim in the passage?
A. It explains why people used reeds and papyrus to make their shoes.
B. It shows how the scientists made their conclusions about when people began wearing shoes.
C. It shows how the scientists made their conclusions about what materials were used to make shoes.
D. It explains why the thickness of bones decreased in fossilized skeletons.