Heather's Investments Will Earn 11% Compounded Annually And, in 30

Heather's investments will earn 11% compounded annually and, in 30 years, she must have $645,000. For the next 20 years she can make year-end contributions of $10,000. She will not be able to make any contributions after 20 years from now. She wants to know if she has to start the $10,000 annual contributions now in order to reach her goal. If not, how many years can she wait before starting the $10,000 annual contributions?

A) She must start now.
B) She can wait for 4 years.
C) She can wait for 8 years.
D) She can wait for 12 years.
E) She can wait for 16 years.