Which of the following is not a geological era?

where r the following ?

I think u forget to write them

president franklin roosevelt supported the tva as part of his first new deal measures approved by congress in 1933. this new agency was designed to control floods, produce electric power, and improve the lives of people living in the tennessee valley. the tva accomplished many of these goals despite problems.

answer; i believe that the correct answer is (c) arctic tundra;