Need help
Which of the following are true about the Paleozoic era?

I. Mammals were common on land and in the oceans.
II. Plants appeared on land for the first time.
III. Seed plants were common by the end of the era.
IV. Arachnids and insects appeared for the first time.
A.
III and IV only
B.
II, III, and IV only
C.
I, II, III, and IV
D.
II and III only