Which life-form was most abundant 250 million years ago?

Question

a. dinosaurs
b.reptiles
c.bony fishes
d.trilobites

I think it's d.

Answer 1

well, they were abundant until they died out about the 250 million years ago.

Answer 2

then what is it supposed to be, reptiles?

Answer 3

I would do with d, assuming they didn't die out then, but at 249million years ago.

Answer 4

oh ok

Answer 5

Trilobites became much less abundant earlier, see here:

http://en.wikipedia.org/wiki/Trilobite

They died out completely 250 millions years ago.