Darcy is buying a new couch that cost $999.00. She has two payment options.

Option 1: Pay with credit card. The card charges 20.00% annual interest and Darcy expects to pay off the charge in 30 days.

Option 2: Take the store promotion of 15 monthly payments of $70 (including tax)

a) Calculate the total cost of each option
b) What is the annual interest rate being charged with Option 2?

Please show your work. ​​