PLS HELP THIS IS WORTH A 100 PTS!!(PLUS I WILL MARK BRAINIEST IF SOMEONE ANSWERS CORRECTY AND FIRST)

A science class is looking at the fossils in different layers of a cliff. They found fossils of fish in lower layers. Which conclusion is best supported by the presence of the fossils?

A
The climate in the area used to be much warmer.

B
The fossils were carried to the area by rain runoff.

C
The area was once a desert.

D
The area used to be underwater.